150 Amazing Science Words That Start With K: Ultimate List

Published On: October 14, 2026

exploer 150 science words that start with K

Science helps us understand how the world works, from tiny cells to distant stars. Learning new scientific words makes these ideas easier to explore. This guide to science words that start with K includes terms from physics, chemistry, biology, astronomy, earth science, medicine, and more.

Some words, such as kelvin and kilogram, describe measurements. Others, such as kinetic energy and karyotype, help explain movement and living things. Each term below includes its origin, a simple meaning, and an example sentence.

Physics and Measurement Words That Start With K

Physics explains motion, energy, forces, and measurements. These science words that start with K help describe how objects move and how scientists measure the world.

Physics K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Kelvin	Named after Lord Kelvin	The SI unit used to measure temperature.	Scientists measured the gas temperature in kelvins.
Kilogram	French and Greek roots	The SI base unit of mass.	The package had a mass of one kilogram.
Kilometer	Greek roots	A unit of length equal to 1,000 meters.	The runner completed a five-kilometer race.
Kilowatt	Greek metric prefix	A unit of power equal to 1,000 watts.	The heater uses one kilowatt of power.
Kilojoule	Greek metric prefix	A unit of energy equal to 1,000 joules.	The label showed the food’s energy in kilojoules.
Kilohertz	Greek metric prefix	A unit of frequency equal to 1,000 hertz.	The signal operated at several kilohertz.
Kilopascal	Metric prefix and Blaise Pascal’s name	A unit used to measure pressure.	The gauge showed a pressure of 100 kilopascals.
Kilovolt	Greek metric prefix	A unit of electrical potential equal to 1,000 volts.	The equipment was tested at a high kilovolt level.
Kilo-ohm	Greek metric prefix	A unit of electrical resistance equal to 1,000 ohms.	The circuit used a ten-kilo-ohm resistor.
Kinematics	Greek	The study of motion without focusing on its causes.	Kinematics helped the class describe the ball’s path.
Kinetics	Greek	The study of motion or, in chemistry, reaction rates.	Chemical kinetics showed how quickly the reaction occurred.
Kinetic energy	Greek	Energy an object has because it is moving.	The moving bicycle had kinetic energy.
Kinetic friction	Greek and Latin roots	Resistance between surfaces sliding against each other.	Kinetic friction slowed the sliding box.
Kinetic theory	Greek	A theory that explains matter through the motion of its particles.	Kinetic theory helped explain how gases behave.
Kinematic viscosity	Greek and Latin roots	A measure of how a fluid flows under gravity or motion.	Engineers measured the oil’s kinematic viscosity.

Chemistry Words That Start With K

Chemistry studies substances, their properties, and how they change. These science words that start with K include chemical compounds, minerals, and useful laboratory methods.

Chemistry K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Krypton	Greek	A noble gas with the chemical symbol Kr.	Krypton can be used in special lighting.
Ketone	German, from chemical terminology	An organic compound containing a carbonyl group between two carbon groups.	Acetone is a common example of a ketone.
Ketal	Chemical terminology	A compound formed from a ketone and alcohol under suitable conditions.	The chemist prepared a ketal during the experiment.
Ketene	German chemical terminology	A reactive organic compound containing a C=C=O group.	Ketene must be handled with care because it is highly reactive.
Kaolin	Chinese place name	A soft clay used in ceramics and other products.	Kaolin was added to the ceramic mixture.
Kaolinite	Named from kaolin	A clay mineral found in many soils and rocks.	The sample contained kaolinite.
Kerosene	Greek and Latin roots	A liquid fuel made from petroleum.	Kerosene contains a mixture of hydrocarbons.
Ksp	Chemical notation	The solubility product constant for a slightly soluble compound.	The student used Ksp to study salt solubility.
Ka	Chemical notation	The acid dissociation constant used to describe acid strength.	The class compared acids using their Ka values.
Kjeldahl method	Named after Johan Kjeldahl	A method used to measure nitrogen in a sample.	The laboratory used the Kjeldahl method to test the food sample.
Keto-enol tautomerism	Greek chemical roots	The change between two related forms of some organic compounds.	Keto-enol tautomerism can affect a compound’s reactions.
Keto acid	Greek and chemical terminology	An organic acid that also contains a ketone group.	The cell used a keto acid in metabolism.
Ketone body	Chemical terminology	A substance made by the liver when it breaks down fat for energy.	The test measured ketone bodies in the sample.
Krypton fluoride	Element name and chemical terminology	A compound of krypton and fluorine used in certain excimer lasers.	Krypton fluoride lasers can produce ultraviolet light.
Kieselguhr	German	A porous material made mainly from fossil diatom remains.	Kieselguhr helped filter the liquid.

Biology Words That Start With K

Biology explores living things and how their bodies work. These science words that start with K cover cells, proteins, and important biological processes.

Biology K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Keratin	Greek	A strong protein found in hair, nails, and the outer skin.	Keratin helps make hair strong.
Kinase	Greek scientific terminology	An enzyme that transfers phosphate groups to other molecules.	The kinase helped control a cell signal.
Kinetochore	Greek	A structure on a chromosome where spindle fibers attach during cell division.	The kinetochore helped move the chromosome.
Karyotype	Greek	An organized picture of an individual’s chromosomes.	The scientist examined the karyotype.
Karyokinesis	Greek	The division of a cell’s nucleus.	Karyokinesis takes place during cell division.
Karyoplasm	Greek	The material inside a cell’s nucleus.	The karyoplasm surrounds the chromosomes.
Karyogamy	Greek	The joining of two cell nuclei.	Karyogamy occurs during some forms of sexual reproduction.
Karyolysis	Greek	The breakdown or fading of a cell nucleus.	The damaged tissue showed signs of karyolysis.
Karyorrhexis	Greek	The breaking apart of a cell nucleus.	Karyorrhexis can occur in dying cells.
Karyomere	Greek	A small nucleus-like structure formed during certain cell divisions.	The researcher studied karyomeres in the developing cells.
Karyosome	Greek	A dense body of material inside a cell nucleus.	The karyosome was visible under the microscope.
Karyotheca	Greek	The membrane surrounding a cell nucleus.	The karyotheca separates the nucleus from the cytoplasm.
Karyology	Greek	The study of cell nuclei and their chromosomes.	Karyology helps scientists study chromosome structure.
Kinesis	Greek	Movement or a change in activity in response to a stimulus.	The organism changed its movement in response to light.
Kleptoparasitism	Greek	A behavior in which one animal steals food collected by another.	Kleptoparasitism occurs in several bird species.

Genetics and Molecular Biology Words That Start With K

Genetics studies DNA, genes, and inherited traits. These science words that start with K describe genetic research and the molecules that help cells function.

Genetics and Molecular Biology K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Kilobase	Metric prefix and nucleotide terminology	A unit equal to 1,000 DNA or RNA bases.	The gene was located within a ten-kilobase region.
Kilobase pair	Metric prefix and DNA terminology	A unit equal to 1,000 base pairs in double-stranded DNA.	The DNA fragment measured five kilobase pairs.
Knockout	English scientific terminology	The removal or disabling of a gene to study its function.	A gene knockout helped reveal the gene’s role.
Knockout gene	English genetics terminology	A gene that has been deliberately disabled in an experimental system.	Researchers studied the knockout gene’s effects.
Knockout mouse	English genetics terminology	A mouse engineered to have a specific gene disabled.	The knockout mouse helped researchers study disease.
Knock-in	English genetics terminology	A method used to add or replace a specific DNA sequence.	The team used knock-in technology to study a gene variant.
Knockdown	English molecular biology terminology	A method that reduces a gene’s activity or expression.	Gene knockdown reduced the amount of a target protein.
K-mer	Computational biology terminology	A short sequence of DNA or RNA made of a set number of letters.	The software counted each K-mer in the DNA sample.
Kozak sequence	Named after Marilyn Kozak	A sequence around a start codon that helps guide protein production in eukaryotes.	The Kozak sequence helped the cell start translation.
Klenow fragment	Named after Hans Klenow	A portion of DNA polymerase I used in molecular biology.	The researcher used the Klenow fragment to fill DNA ends.
Ku protein	Named from its discovery in a patient	A protein complex involved in repairing broken DNA.	Ku protein helped the cell repair damaged DNA.
KRAS gene	Gene symbol	A gene that helps control cell growth and signaling.	Researchers tested the tumor for changes in KRAS.
KIR receptor	Killer-cell immunoglobulin-like receptor terminology	A receptor found on natural killer cells that helps regulate immune responses.	The KIR receptor helped the immune cell recognize its signals.
Killer T cell	English immunology terminology	An immune cell that can destroy infected or abnormal cells.	A killer T cell attacked the infected cell.
Kinesin	Greek	A motor protein that moves materials along structures inside cells.	Kinesin carried cargo through the cell.

Ecology and Organism Words That Start With K

Ecology looks at living things and their surroundings. These science words that start with K include ecological ideas, plants, and animals studied by scientists.

Zoology and Ecology K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Keystone species	English ecological terminology	A species that has a major effect on its ecosystem compared with its abundance.	Sea otters can act as a keystone species in some coastal ecosystems.
K-selected species	Ecology terminology	A species whose life history often favors fewer young and greater investment in each one.	Elephants are often described as K-selected species.
Kin selection	English evolutionary biology terminology	An explanation for behavior that can help relatives pass on shared genes.	Kin selection may explain helping behavior among close relatives.
Kelp	Norwegian	Large brown seaweeds that grow in coastal waters.	Kelp provides food and shelter for marine life.
Kelp forest	English ecological terminology	An underwater habitat formed by dense growth of kelp.	The kelp forest supported many fish species.
Krill	Norwegian	Small shrimp-like marine animals that are important food for many ocean species.	Whales feed on krill in some ocean regions.
Krait	Hindi and regional South Asian roots	A group of venomous snakes in the genus Bungarus.	The krait is part of the study of venomous snakes.
Kakapo	Māori	A large, flightless parrot native to New Zealand.	Conservation teams monitor the endangered kakapo.
Kiwi	Māori	A flightless bird native to New Zealand.	Scientists studied the kiwi’s nesting habits.
Komodo dragon	Named after Komodo Island	A large monitor lizard native to several Indonesian islands.	The Komodo dragon uses its tongue to detect chemical cues.
Kangaroo rat	English zoological terminology	A small rodent adapted to dry habitats in North America.	The kangaroo rat can survive with very little drinking water.
Killer whale	English zoological terminology	A large marine mammal also known as the orca.	The killer whale hunted in a coordinated group.
Kākā	Māori	A forest parrot native to New Zealand.	The kākā fed on nectar and seeds.
Kestrel	French and English roots	A small falcon that often hovers while hunting.	The kestrel hovered above the field.
Koi	Japanese	A domesticated variety of carp often kept in ponds.	The biologist observed the koi in the pond.

Earth Science and Geology Words That Start With K

Earth science explains rocks, landforms, and the processes that shape our planet. These science words that start with K help describe minerals and landscapes.

Geology K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Karst	Named from a region in the Balkans	A landscape shaped by the dissolving of soluble rocks such as limestone.	The karst landscape contained caves and sinkholes.
Karst topography	Regional place name and Greek root	Landforms created as water dissolves soluble rock.	Karst topography can include underground drainage.
Karst aquifer	Regional place name and Latin root	An underground water system within soluble rock.	The town obtained water from a karst aquifer.
Kettle lake	English glacial geology terminology	A lake formed when buried ice melts in glacial deposits.	A kettle lake formed after the ice melted.
Kettle hole	English glacial geology terminology	A hollow left by melting buried ice.	The kettle hole filled with rainwater.
Kame	Scottish geological terminology	A mound or hill of sand and gravel deposited by a glacier.	The hikers climbed a small kame.
Kame terrace	Scottish geological terminology	A flat deposit of glacial sediment along a valley side.	The kame terrace marked an old glacial landscape.
Kame delta	Scottish geological terminology	A delta-shaped deposit formed by meltwater near a glacier.	The geologist mapped the kame delta.
Kame plain	Scottish geological terminology	A broad area of sand and gravel deposited by glacial meltwater.	The kame plain contained layers of glacial sediment.
Kyanite	Greek	A mineral often found in metamorphic rocks.	The rock sample contained blue kyanite.
Kimberlite	Named after Kimberley, South Africa	A type of volcanic rock that can carry diamonds toward Earth’s surface.	The mine explored a kimberlite pipe.
Komatiite	Named after the Komati River region	A rare volcanic rock that formed from very hot, magnesium-rich lava.	The geologist examined ancient komatiite.
Kerogen	Greek	Organic material in sedimentary rock that can form oil and gas when heated over time.	The shale contained kerogen.
Kilauea	Hawaiian	An active volcano on the island of Hawaiʻi.	Scientists monitored volcanic activity at Kilauea.
Krakatoa	Indonesian place name	A volcanic island area in Indonesia known for a major eruption in 1883.	Krakatoa is studied in the history of volcanic eruptions.

Astronomy Words That Start With K

Astronomy studies stars, planets, and other objects in space. These science words that start with K include ideas about orbits, stars, and powerful cosmic events.

Astronomy K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Kepler’s laws	Named after Johannes Kepler	Three laws that describe how planets orbit the Sun.	Kepler’s laws helped explain planetary motion.
Keplerian orbit	Named after Johannes Kepler	An idealized orbit described by Kepler’s laws under gravity.	The satellite followed a nearly Keplerian orbit.
Kuiper Belt	Named after Gerard Kuiper	A region beyond Neptune containing many icy objects.	Pluto is associated with the Kuiper Belt.
Kuiper Belt object	Astronomy terminology	An icy body that orbits the Sun in the Kuiper Belt.	The telescope observed a distant Kuiper Belt object.
Kilonova	Greek-derived scientific term	A bright event produced when dense stellar remnants, such as neutron stars, merge.	Astronomers studied the kilonova for signs of heavy elements.
Kelvin–Helmholtz mechanism	Named after Lord Kelvin and Hermann von Helmholtz	A process in which gravitational contraction releases energy as an object shrinks.	The Kelvin–Helmholtz mechanism helps explain energy from young stars.
K-type star	Stellar classification terminology	A star with an orange appearance and a surface cooler than the Sun’s.	A K-type star can be a target in planet searches.
K-dwarf	Stellar classification terminology	A dwarf star in spectral class K.	The researchers studied a K-dwarf for orbiting planets.
K-correction	Astronomy terminology	A correction used to compare an object’s brightness across different redshifts and observing bands.	The team applied a K-correction to the galaxy data.
Kozai mechanism	Named after Yoshihide Kozai	An orbital effect that can change an object’s orbit and tilt under the influence of another body.	The Kozai mechanism may alter an object’s orbital shape.
Kirkwood gaps	Named after Daniel Kirkwood	Gaps in the asteroid belt linked to orbital resonances with Jupiter.	Astronomers mapped the Kirkwood gaps in the asteroid belt.
Kreutz sungrazers	Named after Heinrich Kreutz	A family of comets that pass extremely close to the Sun.	Solar observatories have detected Kreutz sungrazers.
Kepler Space Telescope	Named after Johannes Kepler	A NASA space telescope designed to search for planets around other stars.	The Kepler Space Telescope found thousands of planet candidates.
Kepler equation	Named after Johannes Kepler	An equation used to calculate the position of an object in an elliptical orbit.	The program solved the Kepler equation to estimate the planet’s position.
Keplerian motion	Named after Johannes Kepler	Motion that follows the ideal laws of orbital motion under gravity.	The model described the satellite’s Keplerian motion.

Medical and Human Biology Words That Start With K

Medical science studies the body, health, and disease. These science words that start with K include body structures and terms used in clinical research.

Medical Science K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Kidney	Old English	An organ that filters blood and helps remove waste through urine.	Each kidney helps balance water and salts in the body.
Kidney cortex	English anatomical terminology	The outer region of the kidney.	The kidney cortex contains many filtering structures.
Kidney medulla	Latin anatomical terminology	The inner region of the kidney.	The kidney medulla helps concentrate urine.
Kidney stone	English medical terminology	A hard deposit that forms from substances in urine.	The scan showed a small kidney stone.
Keratocyte	Greek	A cell found in the cornea of the eye.	The researcher studied how a keratocyte responds to injury.
Keratitis	Greek	Inflammation of the cornea.	The doctor checked the eye for signs of keratitis.
Keratoconus	Greek	An eye condition in which the cornea becomes thinner and bulges outward.	Keratoconus can change the shape of the cornea.
Keratoplasty	Greek	Surgery to repair or replace part of the cornea.	The patient learned about keratoplasty from the eye specialist.
Kyphosis	Greek	A forward curve of the upper spine that is greater than usual.	The specialist assessed the patient’s kyphosis.
Kyphoplasty	Greek and medical terminology	A procedure used to treat certain spinal compression fractures.	The doctor discussed kyphoplasty as a possible treatment.
Keloid	Greek	A raised scar caused by excess scar tissue growth.	The keloid grew beyond the original wound.
Ketosis	Greek chemical terminology	A state in which the body makes more ketones for energy.	The laboratory test measured ketone levels during ketosis.
Ketoacidosis	Greek medical terminology	A dangerous buildup of acids called ketones in the blood.	Ketoacidosis requires urgent medical care.
Ketonemia	Greek medical terminology	An increased level of ketones in the blood.	The blood test detected ketonemia.
Ketonuria	Greek medical terminology	The presence of ketones in urine.	The urine test showed ketonuria.

Mathematics and Computing Words That Start With K

Mathematics and computing help scientists analyze data and solve problems. These science words that start with K are used in statistics, algorithms, and mathematical models.

Mathematics K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Knot theory	English mathematical terminology	A branch of mathematics that studies loops and knots.	Knot theory can help researchers study complex shapes.
Knot invariant	English mathematical terminology	A property of a mathematical knot that stays unchanged under allowed transformations.	The mathematician calculated a knot invariant.
Knot diagram	English mathematical terminology	A drawing that represents a knot and its crossings.	The student compared two knot diagrams.
Klein bottle	Named after Felix Klein	A mathematical surface with no distinct inside and outside.	A model helped the class explore the Klein bottle.
Kronecker delta	Named after Leopold Kronecker	A function equal to one when two indices match and zero otherwise.	The equation used the Kronecker delta.
Kronecker product	Named after Leopold Kronecker	A way to combine two matrices into a larger matrix.	The program calculated the Kronecker product.
Kernel	Old English and mathematical usage	In mathematics, a central set or function defined by the problem being studied.	The researcher examined the kernel of the transformation.
Kernel function	Mathematics and computing terminology	A function used to measure similarity or support a mathematical operation.	The model used a kernel function to compare data points.
K-means clustering	Statistical and computing terminology	A method that groups data points into clusters.	K-means clustering grouped similar measurements.
K-nearest neighbors	Statistical and computing terminology	A method that predicts a result using the closest data points.	K-nearest neighbors classified the sample.
Kalman filter	Named after Rudolf E. Kálmán	A method for estimating a changing state from uncertain measurements.	The robot used a Kalman filter to estimate its position.
Karnaugh map	Named after Maurice Karnaugh	A diagram used to simplify Boolean logic expressions.	The engineer used a Karnaugh map to simplify the circuit.
Knapsack problem	Named for the knapsack selection problem	A mathematical problem about choosing items under a limited capacity.	The class solved a knapsack problem with limited space.
Kolmogorov complexity	Named after Andrey Kolmogorov	A measure related to the shortest computer description of information.	The researcher compared the Kolmogorov complexity of two strings.
Kolmogorov–Smirnov test	Named after Andrey Kolmogorov and Nikolai Smirnov	A statistical test that compares distributions.	The scientist used the Kolmogorov–Smirnov test to compare the data.

Laboratory and Engineering Words That Start With K

Laboratories and engineering use special tools, laws, and methods to test ideas. These science words that start with K describe instruments and processes used in research.

Physics K terms, their origins, meanings, and example sentences
Word	Origin	Meaning	Example Sentence
Klystron	Greek	An electronic device that amplifies or generates high-frequency radio waves.	The radar system used a klystron.
Kymograph	Greek	An instrument that records changes in a signal over time.	The kymograph recorded changes in muscle activity.
Kymography	Greek	The process of recording or studying movement or changes over time using a kymograph or related imaging method.	The research team used kymography to study movement.
Kelvin bridge	Named after Lord Kelvin	A circuit used to measure very low electrical resistance accurately.	The technician used a Kelvin bridge to test the wire.
Kelvin probe	Named after Lord Kelvin	An instrument used to measure differences in electrical potential between surfaces.	The Kelvin probe measured the sample’s surface potential.
Kelvin probe force microscopy	Named after Lord Kelvin	A scanning probe method used to map surface potential at very small scales.	The lab used Kelvin probe force microscopy to study the material.
Knudsen number	Named after Martin Knudsen	A number that compares the mean free path of gas particles with a system’s size.	The engineer calculated the Knudsen number for the tiny channel.
Knudsen diffusion	Named after Martin Knudsen	Gas movement through very narrow spaces where particle-wall collisions matter.	Knudsen diffusion affected gas flow through the pores.
Knudsen cell	Named after Martin Knudsen	A device used to study evaporation and vapor pressure under controlled conditions.	The scientist heated the sample inside a Knudsen cell.
Knudsen pump	Named after Martin Knudsen	A pump that uses gas movement in small channels under certain temperature conditions.	The team tested a Knudsen pump in the small device.
Kirchhoff’s laws	Named after Gustav Kirchhoff	Rules used to analyze current and voltage in electrical circuits.	Kirchhoff’s laws helped solve the circuit problem.
Kopp’s law	Named after Hermann Kopp	A historical rule relating the heat capacity of a compound to its components.	The chemist discussed Kopp’s law while studying heat capacity.
Kohlrausch’s law	Named after Friedrich Kohlrausch	A principle describing the independent contributions of ions to conductivity at very low concentrations.	Kohlrausch’s law helped explain the solution’s conductivity.
Kutta–Joukowski theorem	Named after Martin Kutta and Nikolai Joukowski	A theorem that relates lift on a body to fluid circulation and flow speed.	The engineer used the Kutta–Joukowski theorem to study lift.
Kundt’s tube	Named after August Kundt	A tube used to study sound waves and patterns caused by vibrations.	The class used Kundt’s tube to observe sound-wave patterns.

Conclusion

These science words that start with K show how one letter can connect many fields of study. From kelvin and kinetic energy to karyotype, karst, and Kuiper Belt, each term helps describe a different part of the natural world.

Learning these words can build scientific vocabulary and make school topics easier to understand. Start with the terms related to your current subject, read each example sentence, and use the words in your own explanations.

Frequently Asked Questions

What are some common science words that start with K?

Common examples include kelvin, kilogram, kilometer, kinetic energy, kinematics, krypton, keratin, kidney, and karyotype.

What are some biology words that start with K?

Biology terms include keratin, kinase, kinetochore, karyotype, karyokinesis, karyoplasm, and kinesin. They describe proteins, cell structures, and biological processes.

Which physics words start with K?

Physics includes kelvin, kinetic energy, kinematics, kinetics, kilowatt, kilojoule, kilohertz, and kinematic viscosity.

What chemistry words start with K?

Examples include krypton, ketone, ketal, ketene, kaolin, kaolinite, kerosene, and the chemical notation Ksp.

What does K mean in science?

The meaning depends on the context. The symbol K represents kelvin, the SI unit of thermodynamic temperature. In chemistry, K is also the chemical symbol for potassium.

Why is kinetic energy important?

Kinetic energy is the energy an object has because it moves. It helps explain motion in everyday activities, machines, sports, and many physical processes.

What is a karyotype?

A karyotype is an organized display of an individual’s chromosomes. Scientists and medical professionals can use it to examine chromosome number and structure.

What is the Kuiper Belt?

The Kuiper Belt is a region beyond Neptune that contains many icy objects orbiting the Sun. Pluto is one of the well-known objects associated with this region.

Where can students learn more about astronomy terms?

Students can explore NASA’s Universe Glossary, which explains astronomy concepts, including kelvin and Kepler’s laws, in more detail.