140 Science Words That Start With L (With Meanings & Examples)

Science is full of amazing words, and many of them start with the letter L. Learning these words helps students, teachers, and science lovers build a strong science vocabulary. This guide shares a complete list of science words beginning with L, explained with meanings and examples. You will see them divided into subjects like physics, chemistry, biology, earth science, astronomy, mathematics, medicine, and forensics. Each section includes easy science words and also more advanced science vocabulary.

This article goes beyond a plain list. Instead, you will discover how each word is used in science. You will also learn example sentences to make the meaning clear. Whether you want easy science words for kids or advanced science terms starting with L, this guide has everything you need Science Words That Start With L.

Physics Words That Start With L

Word	Meaning	Example Sentence
Laser	Device that produces a focused beam of light	Doctors use a laser for eye surgery.
Luminosity	Brightness of a star or light source	The Sun’s luminosity affects Earth’s climate.
Lightwave	Wave of light energy	A lightwave travels faster than sound.
Linear Motion	Movement in a straight line	A ball rolling forward shows linear motion.
Laws of Motion	Newton’s three principles of motion	Engineers design rockets using the laws of motion.
Lever	A simple machine used to lift objects	A crowbar acts as a lever to move heavy items.
Load	The weight carried by a structure	The bridge supports a heavy load.
Lepton	A fundamental particle, like an electron	Neutrinos are tiny particles that belong to the lepton family.
Lens	Curved glass that bends light rays	A microscope uses a lens to magnify cells.
Latent Heat	Heat absorbed without changing temperature	Ice absorbs latent heat when melting.

Chemistry Words That Start With L

Word	Meaning	Example Sentence
Ligand	Molecule that binds to a metal atom	A ligand helps form stable complexes.
Lattice	Regular arrangement of particles in solids	Salt crystals have a lattice structure.
Luminol	Chemical that glows in contact with blood	Forensic experts used luminol at the crime scene.
Lactose	Sugar found in milk	Some people cannot digest lactose easily.
Lipid	Fat molecules important in biology and chemistry	Lipids store energy in living cells.
Liquid	State of matter with no fixed shape but fixed volume	Water is a liquid at room temperature.
Limiting Reagent	The reactant that stops a chemical reaction	The limiting reagent decides how much product forms.
Litmus	Dye used to test acidity or alkalinity	Blue litmus paper turns red in acid.
Lanthanides	Rare earth metals on the periodic table	Lanthanides are used in electronics and magnets.
Lewis Acid	Substance that accepts an electron pair	Boron trifluoride acts as a Lewis acid.

Biology Words That Start With L

Word	Meaning	Example Sentence
Lysosome	Organelle that digests waste in cells	Lysosomes keep cells clean by breaking waste.
Liver	Organ that detoxifies blood	The liver processes nutrients after eating.
Larva	Early stage of insect development	A butterfly begins life as a larva.
Leukocyte	White blood cell that fights infections	The doctor checked his leukocyte count.
Ligament	Tissue connecting bones at joints	A knee ligament injury needs time to heal.
Lymph	Fluid that carries white blood cells	Lymph flows through the lymphatic system.
Lactic Acid	Substance formed during muscle activity	Muscles produce lactic acid after exercise.
Lung	Organ used for breathing	Smoking damages the lungs.
Lactation	Production of milk in mammals	Lactation provides food for newborn mammals.
Leaf	Main organ of photosynthesis in plants	A green leaf makes food for the plant.

Earth Science Words That Start With L

Word	Meaning	Example Sentence
Landslide	Sudden fall of rocks or soil down a slope	Rain caused a landslide on the mountain road.
Limestone	Sedimentary rock made of calcium carbonate	Limestone is used in making cement.
Lithosphere	Earth’s rigid outer layer	The lithosphere includes the crust and upper mantle.
Lava	Molten rock from a volcano	Lava flowed after the volcanic eruption.
Latitude	Distance north or south of the equator	The city lies at a latitude of 30°N.
Lake	Large inland body of water	The fish live in the deep lake.
Layer	A distinct horizontal part of Earth’s crust	Scientists study soil layers to learn about history.
Landform	Natural feature of the Earth’s surface	Mountains and valleys are landforms.
Lagoon	Shallow body of water separated from the sea	The lagoon is home to many birds.
Loess	Fine, fertile soil made of windblown dust	Farmers grow crops on less-rich soil.

Astronomy Words That Start With L

Word	Meaning	Example Sentence
Light-year	Distance light travels in one year	The star is 4 light-years away.
Lunar	Related to the Moon	A lunar eclipse happens when Earth blocks sunlight.
Libration	Apparent wobble of the Moon	Libration lets us see more of the lunar surface.
Luminosity	Brightness of a star	Astronomers measure luminosity to compare stars.
Lunar Surface	Outer layer of the Moon	Astronauts walked on the lunar surface.
Lunar Crater	Hollow on the Moon made by impact	Telescopes show lunar craters clearly.
Local Group	A cluster of galaxies including the Milky Way	The Milky Way belongs to the Local Group.
Low Mass Star	Star smaller than the Sun	A low mass star burns fuel slowly.
Launch	Sending a spacecraft into space	NASA prepared for the rocket launch.
Longitude (Astronomy use)	Angular distance east or west	The star’s position was marked by its longitude.

Mathematics Words That Start With L

Word	Meaning	Example Sentence
Logarithm	Inverse of exponentiation	A logarithm makes large numbers easier to handle.
Linear Equation	Equation forming a straight line	y = 2x + 3 is a linear equation.
Limit	Value approached in calculus	The function approaches a limit as x → 0.
Line Graph	Graph showing data with lines	The teacher used a line graph to explain growth.
Length	Measurement of distance	The length of the rope is 5 meters.
Logic	Method of reasoning in mathematics	Logic helps solve tough problems.
LCM (Least Common Multiple)	Smallest number divisible by others	The LCM of 4 and 6 is 12.
Linear Function	Function with constant slope	f(x) = 2x is a linear function.
Lateral Surface Area	Area of sides of a 3D figure	The lateral surface area of a cylinder is 2πrh.
Laplace Transform	Tool in advanced math to solve equations	Engineers use the Laplace transform for control systems.

Medical & Forensic Science Words That Start With L

Word	Meaning	Example Sentence
Larynx	Voice box in the throat	The singer strained her larynx.
Lesion	Abnormal tissue damage	The doctor treated the skin lesion.
Leukocyte	White blood cell	A high leukocyte count shows infection.
Lymph Node	Small structure filtering lymph fluid	The swollen lymph node showed infection.
Luminol	Chemical used in forensics to detect blood	Investigators sprayed luminol at the crime scene.
Lung	Organ for breathing	Healthy lungs are vital for life.
Ligature	Something used for tying	Forensics found a ligature mark on the neck.
Lumbar	Related to the lower back	He felt pain in the lumbar region.
Lactation	Milk production in mammals	Lactation supports newborn babies.
Liposuction	Surgery to remove fat	The patient had liposuction for health reasons.

Environmental Science Words That Start With L

Word	Meaning	Example Sentence
Landfill	Site for waste disposal	The city built a new landfill for garbage.
Light Pollution	Bright artificial light that affects nature	Light pollution makes it hard to see stars.
Leachate	Liquid from waste seeping into soil	Leachate contaminated the groundwater near the landfill.
Low Carbon	Activity that reduces carbon emissions	Solar panels are part of a low carbon future.
Litter	Waste materials scattered in the environment	Volunteers cleaned litter from the park.
Local Ecosystem	Natural community in one area	Frogs are part of the local ecosystem.
Life Cycle Assessment	Study of product impact from start to end	Engineers used a life cycle assessment for packaging.
Land Degradation	Decline in land quality	Overgrazing caused land degradation in the village.
Limiting Factor	A resource that controls population growth	Water shortage is a limiting factor for plants.
Low Impact Development	Building method that reduces harm to nature	Low impact development protects urban rivers.

Geology Words That Start With L

Word	Meaning	Example Sentence
Lava Flow	Stream of molten rock	The volcano created a huge lava flow.
Lapilli	Small volcanic rocks	Lapilli fell during the eruption.
Lithification	Process of turning sediment into rock	Sand became sandstone through lithification.
Laccolith	Dome-shaped intrusion of magma	A laccolith formed beneath the mountain.
Layered Rock	Rock with visible layers	The canyon walls show layered rock.
Laterite	Soil rich in iron and aluminum	Laterite is used in construction.
Linear Valley	Straight valley formed by faults	The rift is a linear valley.
Loam	Fertile soil mixture	Farmers grow crops on loam soil.
Lava Plateau	Flat land formed by lava	India has a large lava plateau called Deccan Traps.
Lithology	Study of rocks and minerals	Lithology helps geologists identify formations.

Botany Words That Start With L

Word	Meaning	Example Sentence
Leaflet	A small part of a compound leaf	The clover has three leaflets.
Lamina	The flat part of a leaf	Photosynthesis happens in the lamina.
Lenticel	Small pores on stems for gas exchange	Lenticels help plants breathe.
Leaf Vein	The vascular structure in leaves	The maple leaf has strong leaf veins.
Leaf Blade	Broad part of a leaf	The banana has a large leaf blade.
Latex	Milky fluid in plants	Rubber trees produce latex.
Locule	Chamber in fruit or ovary	Tomatoes have many locules filled with seeds.
Leaf Axil	Angle between stem and leaf	Buds grow from the leaf axil.
Liana	Woody climbing plant	The rainforest has many lianas.
Leaf Scar	Mark left after a leaf falls	Leaf scars help identify tree species.

Zoology Words That Start With L

Word	Meaning	Example Sentence
Larva	Early life stage of animals	A frog begins life as a larva.
Lepidoptera	Order of butterflies and moths	Lepidoptera are known for colorful wings.
Lizard	Cold-blooded reptile	The lizard basked in the sun.
Lion	Large carnivorous mammal	The lion is called the king of the jungle.
Lemming	Small rodent found in Arctic regions	Lemmings migrate in large groups.
Lamprey	Jawless fish with sucking mouth	Lampreys attach to other fish to feed.
Locust	Grasshopper that forms swarms	Farmers feared the locust invasion.
Lemur	Primate found in Madagascar	Lemurs live in rainforest trees.
Lobster	Marine crustacean with claws	Lobster is a popular seafood.
Lungfish	Fish that can breathe air	The lungfish survives droughts by breathing air.

Genetics Words That Start With L

Word	Meaning	Example Sentence
Locus	Position of a gene on a chromosome	Each gene has a locus on DNA.
Linkage	Genes inherited together	Linkage explains why some traits appear together.
Ligation	Process of joining DNA fragments	Scientists used ligation in genetic experiments.
Library (DNA)	Collection of cloned DNA sequences	A DNA library is stored in labs.
Lytic Cycle	Viral cycle that destroys host cell	The lytic cycle kills infected cells.
Lysogeny	Viral DNA integrated into host	Lysogeny lets viruses stay hidden.
Loss-of-function Mutation	Mutation reducing gene activity	A loss-of-function mutation caused the disorder.
Lethal Allele	Gene that can cause death when present	Some plants carry lethal alleles.
Lineage	Family or evolutionary history	Humans share a lineage with apes.
Long Arm (Chromosome)	Longer section of a chromosome	Scientists studied the long arm of chromosome 7.

Technology & Engineering Words That Start With L

Word	Meaning	Example Sentence
Laser Cutter	Machine that cuts with a laser beam	Engineers used a laser cutter for precision.
Logic Gate	Basic unit of digital circuits	Computers depend on logic gates.
Load Resistance	Resistance in a circuit	Load resistance affects current flow.
Latency	Delay in data transfer	Low latency is key for online games.
Linear Motor	Motor producing straight-line motion	A train uses a linear motor for speed.
Lithium Battery	Rechargeable power source	Smartphones use lithium batteries.
Local Area Network (LAN)	Computer network in small area	The office computers share a LAN.
Lift Force	Upward force in flight	Airplanes use lift force to stay in the air.
Load Balancer	Device that distributes network traffic	Servers use a load balancer to prevent crashes.
Logic Programming	Programming using rules and logic	AI systems often use logic programming.

Psychology & Social Science Words That Start With L

Word	Meaning	Example Sentence
Learning	Process of gaining knowledge	Learning improves with practice.
Language	System of communication	Language is key to human culture.
Latent Learning	Knowledge gained without immediate use	Rats show latent learning in mazes.
Long-term Memory	Memory lasting for long periods	Long-term memory stores childhood events.
Limbic System	Brain part linked to emotions	The limbic system controls fear and joy.
Locus of Control	Belief about control over events	She had an internal locus of control.
Logical Thinking	Reasoning based on facts	Science requires logical thinking.
Leadership	Ability to guide others	Good leadership inspires teamwork.
Libido	Human sexual drive	Freud described libido as basic energy.
Learned Helplessness	Condition from repeated failure	Learned helplessness prevents motivation.

Conclusion

This guide covered 140 science words that start with L. You explored them by subject, difficulty level, and even through example sentences. From luminosity in physics to liver function in biology and light-year in astronomy, each word showed the importance of language in science.

Understanding this list of science words beginning with L helps students, teachers, and curious readers build confidence. With both easy science words and advanced science vocabulary, this guide works as a mini science dictionary. Keep exploring new science words, and you will see how language connects every part of knowledge.