130 Science Words Starting With G – Full Glossary & Uses

Introduction to Science Words Beginning With G

Science is full of special words that explain ideas, objects, and processes. Knowing the right science vocabulary starting with G can make learning easier and more fun Science Words Starting With G. These words appear in biology, chemistry, physics, astronomy, and earth science. Whether you are a student, teacher, or science lover, a glossary of science words G helps you understand and remember important concepts.

The letter G covers a wide range of topics. From gravity to genetics, and from galaxy to geology, each term has its own meaning and use. This guide gives you a complete science dictionary G words list with definitions and examples. It is a helpful resource for building knowledge and improving your understanding of the natural world.

Biology Terms Starting With G

Word	Meaning	Example
Genetics	Study of genes and heredity	Genetics explains how traits are passed from parents to children.
Genome	Complete set of genetic material in an organism	Scientists mapped the human genome in 2003.
Gene Therapy	Treatment that changes a person’s genes to cure disease	Gene therapy may help treat inherited disorders.
Gamete	Reproductive cell, sperm or egg	The union of gametes forms a zygote.
Genotype	The genetic makeup of an organism	Your genotype influences physical traits like eye color.
Germination	Process of a seed starting to grow	Germination begins when seeds absorb water.
Gland	Organ that makes hormones or other fluids	The thyroid gland controls metabolism.
Glycolysis	Breakdown of glucose to release energy	Glycolysis happens in the cell’s cytoplasm.
Glucose	Simple sugar used for energy in cells	The body uses glucose for fuel.
Growth Hormone	Hormone that stimulates growth and cell reproduction	Growth hormone levels are higher in children.
Green Algae	Plant-like organisms that live in water	Green algae produce oxygen through photosynthesis.
Gizzard	Muscular organ in birds that grinds food	Chickens use their gizzard to crush grains.
Gastrulation	Early stage in embryo development	Gastrulation forms the body’s basic layers.
Germ Cell	Cell that develops into a gamete	Germ cells are found in reproductive organs.
Glycoprotein	Protein with sugar attached	Glycoproteins play a role in cell signaling.

Chemistry Terms Starting With G

Word	Meaning	Example
Gas	State of matter with no fixed shape or volume	Air is a mixture of gases.
Gas Chromatography	Technique for separating chemical mixtures	Gas chromatography identifies compounds in samples.
Gaseous State	Matter in gas form	Water vapor is the gaseous state of water.
Glycerin	Thick, sweet liquid used in products	Glycerin is used in soap making.
Glycol	Organic compound with two hydroxyl groups	Ethylene glycol is used in antifreeze.
Glycoside	Compound where sugar is bound to another molecule	Some plant glycosides have medicinal uses.
Galvanic Cell	Device that produces electricity from a reaction	A battery is a type of galvanic cell.
Gibbs Free Energy	Energy available for work in a system	Negative Gibbs free energy means a reaction is spontaneous.
Gold (Element)	Precious metal with symbol Au	Gold is used in electronics and jewelry.
Germanium	Metalloid element used in electronics	Germanium is used in fiber optics.
Gravimetric Analysis	Method to measure a substance’s mass	Gravimetric analysis is used in chemistry labs.
Gas Hydrate	Solid formed from gas and water	Methane gas hydrates exist under the ocean floor.
Green Chemistry	Designing products to reduce waste and pollution	Green chemistry helps protect the environment.
Glass Transition	Change from hard to rubbery state in polymers	Plastic softens at its glass transition temperature.
Geochemical Cycle	Movement of elements through Earth systems	The carbon geochemical cycle affects climate.

Physics Terms Starting With G

Word	Meaning	Example
Gravity	Force that attracts objects toward each other	Gravity keeps planets in orbit.
Gravitational Force	Attraction between two masses	The Moon’s gravitational force causes tides.
Gravitational Waves	Ripples in space-time from massive events	Gravitational waves were detected in 2015.
Gyroscope	Device that measures orientation	Airplanes use gyroscopes for navigation.
Gamma Radiation	High-energy electromagnetic waves	Gamma radiation comes from radioactive decay.
Gamma Rays	Short wavelength, high-energy light	The Sun emits gamma rays during solar flares.
Galvanometer	Instrument that detects electric current	A galvanometer measures small currents.
Gauge Boson	Particle that carries fundamental forces	Photons are gauge bosons for electromagnetism.
Geodesic	Shortest path between two points in curved space	Light follows a geodesic around massive objects.
G-Force	Acceleration felt as weight	Astronauts experience high g-forces during launch.
Ground State	Lowest energy level of an atom	Electrons naturally return to the ground state.
Gas Laws	Rules about pressure, volume, and temperature	Boyle’s Law is a type of gas law.
Gradient	Rate of change in a field	Temperature gradient affects weather patterns.
Glass Fiber	Strong, thin fiber made from glass	Glass fiber is used in insulation.
Gyromagnetic Ratio	Ratio of magnetic moment to angular momentum	Gyromagnetic ratio is important in MRI machines.

Astronomy Terms Starting With G

Word	Meaning	Example
Galaxy	Group of stars, dust, and gas	The Andromeda galaxy is closest to the Milky Way.
Galactic Cluster	Group of galaxies bound by gravity	The Virgo Cluster is a galactic cluster.
Galactic Core	Dense center of a galaxy	The Milky Way’s galactic core has a black hole.
Geosynchronous Orbit	Orbit matching Earth’s rotation	Weather satellites use geosynchronous orbit.
Geostationary Satellite	Satellite that stays over one point on Earth	TV signals are sent from geostationary satellites.
Great Red Spot	Storm on Jupiter	The Great Red Spot has lasted for centuries.
Gravitational Lensing	Bending of light by gravity	Gravitational lensing can magnify distant galaxies.
Globular Cluster	Dense group of old stars	Globular clusters orbit the Milky Way.
Galactic Halo	Outer region of a galaxy	The galactic halo contains old stars.
Gamma-ray Burst	Short, intense burst of gamma rays	Gamma-ray bursts are the brightest events in space.
Galactic Plane	Main disk of a spiral galaxy	Our solar system is near the galactic plane.
Galactic Year	Time for the Sun to orbit the galaxy	A galactic year is about 225 million years.
Giant Star	Large, bright star	Betelgeuse is a red giant star.
Gas Giant	Large planet mostly made of gas	Jupiter is a gas giant.
Gravitational Collapse	When gravity pulls matter inward	Gravitational collapse forms black holes.

Earth & Environmental Science Terms Starting With G

Word	Meaning	Example
Geology	Study of Earth’s structure and materials	Geology helps find mineral resources.
Geophysics	Physics of the Earth	Geophysics explores earthquakes and magnetism.
Geomorphology	Study of landforms and their processes	Geomorphology explains how mountains form.
Geochemical Cycle	Movement of elements through Earth	The water geochemical cycle includes evaporation and rain.
Geothermal Energy	Heat from Earth’s interior	Iceland uses geothermal energy for electricity.
Greenhouse Effect	Warming caused by trapped heat	The greenhouse effect affects climate change.
Ground Water	Water stored underground	Farmers use ground water for irrigation.
Glacier	Large mass of moving ice	The glacier slowly flows toward the sea.
Glacial Erosion	Wearing away of land by glaciers	Glacial erosion shapes valleys and mountains.
Gas Hydrate	Ice-like solid with gas trapped inside	Gas hydrates are found under polar oceans.
Grain Size	Size of particles in rocks or soil	Grain size affects soil drainage.
Geotechnical Engineering	Study of soil and rock for construction	Geotechnical engineers test ground stability.
Gravel	Small rock fragments	Gravel is used in road construction.
Ground Subsidence	Sinking of Earth’s surface	Pumping too much ground water causes subsidence.
Geospatial Data	Data linked to locations on Earth	Satellites collect geospatial data for maps.

Medical Science Terms Starting With G

Word	Meaning	Example
Gastroenterology	Study of the digestive system	Gastroenterology focuses on stomach and intestine health.
Glaucoma	Eye disease causing vision loss	Glaucoma damages the optic nerve.
Graft	Tissue transplanted from one site to another	Skin grafts help burn victims heal.
Glycogen	Stored form of glucose in the body	The liver stores glycogen for energy.
Gram-positive Bacteria	Bacteria that retain crystal violet stain	Gram-positive bacteria appear purple under a microscope.
Gram-negative Bacteria	Bacteria that do not retain crystal violet stain	Gram-negative bacteria are resistant to some antibiotics.
Genetic Disorder	Disease caused by DNA changes	Cystic fibrosis is a genetic disorder.
Gynecology	Medical field for women’s health	Gynecology covers pregnancy and reproductive care.

Botany Terms Starting With G

Word	Meaning	Example
Gametophyte	Stage in plant life cycle producing gametes	Moss gametophytes are green and leafy.
Geotropism	Plant growth in response to gravity	Roots grow downward due to geotropism.
Guard Cell	Cell controlling leaf openings	Guard cells regulate water loss in plants.
Greenhouse	Structure for growing plants	A greenhouse protects plants from cold weather.
Grafting	Joining two plants to grow as one	Grafting is used in fruit tree farming.
Grassland	Ecosystem dominated by grasses	Grasslands are home to grazing animals.
Germplasm	Genetic material of plants	Seed banks store germplasm for future crops.
Grain	Small, hard seed of cereal plants	Wheat grain is used for flour.

Geography Terms Starting With G

Word	Meaning	Example
GIS (Geographic Information System)	System for mapping and analyzing location data	GIS is used for urban planning.
Grid Reference	System to locate places on a map	The grid reference shows exact coordinates.
Gulf	Large inlet of the sea	The Gulf of Mexico borders the US and Mexico.
Geyser	Hot spring that shoots water and steam	Old Faithful is a famous geyser in Yellowstone.
Gorge	Deep, narrow valley	The Grand Canyon is a massive gorge.
Glacier Melt	Water from melting glaciers	Glacier melt feeds rivers in summer.
Global Positioning System (GPS)	Satellite navigation system	GPS helps find directions anywhere in the world.
Globalization	Process linking countries economically and culturally	Globalization increases global trade and travel.

Engineering Terms Starting With G

Word	Meaning	Example
Gear	Rotating machine part with teeth	Gears transmit power in engines.
Generator	Machine that produces electricity	A wind turbine is a type of generator.
Gradient Descent	Method to find minimum value in calculations	Gradient descent is used in AI training.
Gas Turbine	Engine powered by gas combustion	Jet planes use gas turbines.
Grounding	Connecting to the earth for safety	Electrical grounding prevents shocks.
Galvanization	Coating metal with zinc to prevent rust	Steel beams are protected by galvanization.
Gate Valve	Device to control liquid flow	A gate valve stops water in pipelines.
Gearbox	Set of gears controlling speed	The gearbox shifts a car’s transmission.

Mathematics Terms Starting With G

Word	Meaning	Example
Geometry	Study of shapes and sizes	Geometry covers circles, triangles, and angles.
Gradient	Slope of a line or surface	The gradient of the hill is steep.
Graph Theory	Study of networks of nodes and edges	Graph theory is used in social network analysis.
Gaussian Distribution	Bell-shaped statistical curve	Height data often follows a Gaussian distribution.
Group Theory	Study of mathematical groups	Group theory explains symmetry in physics.
Grid	Network of horizontal and vertical lines	The graph paper has a square grid.
Greatest Common Divisor (GCD)	Largest number dividing two integers	The GCD of 12 and 18 is 6.
Geometric Mean	Type of average using multiplication	The geometric mean of 4 and 16 is 8.

Meteorology Terms Starting With G

Word	Meaning	Example
Gust	Short, strong burst of wind	A gust of wind knocked over the umbrella.
Gale	Very strong wind	The gale damaged coastal houses.
Ground Fog	Fog forming near the ground	Morning ground fog reduced visibility.
Graupel	Soft hail or snow pellets	Graupel fell during the winter storm.
Greenhouse Gas	Gas that traps heat in the atmosphere	Carbon dioxide is a major greenhouse gas.
Global Warming	Rise in Earth’s average temperature	Global warming affects sea levels.
Gust Front	Boundary of cool air from a thunderstorm	A gust front can bring sudden wind shifts.
Growing Season	Time when plants can grow	The growing season varies by climate.

Marine Science Terms Starting With G

Word	Meaning	Example
Gulf Stream	Warm ocean current	The Gulf Stream affects European climate.
Groundfish	Fish living near the ocean floor	Cod is a common groundfish.
Gill	Organ fish use to breathe	Fish take oxygen from water using gills.
Gyre	Large circular ocean current	The North Pacific Gyre collects floating plastic.
Gravel Beach	Beach covered with small stones	The gravel beach made walking difficult.
Gas Exchange	Transfer of gases between organisms and environment	Fish perform gas exchange through gills.
Giant Kelp	Large seaweed species	Giant kelp forms underwater forests.
Gray Whale	Migratory baleen whale	Gray whales travel from Alaska to Mexico.

Technology Terms Starting With G

Word	Meaning	Example
GPU (Graphics Processing Unit)	Processor for graphics and AI	GPUs speed up 3D rendering.
Gateway	Device that connects networks	The router acts as a gateway to the internet.
Gigabyte	Unit of digital storage	One gigabyte equals 1024 megabytes.
Grid Computing	Using many computers for one task	Grid computing used for scientific research.
Global System for Mobile (GSM)	Mobile phone network standard	GSM phones work worldwide.
Geotagging	Adding location to digital content	Photos can have geotagging data.
GUI (Graphical User Interface)	Visual way to interact with software	Windows has a friendly GUI.
Gesture Recognition	Technology to detect body movements	Gesture recognition used in gaming consoles.

Science Words in the Field of Psychology

Word	Meaning	Example
Gestalt	A psychological theory emphasizing patterns and wholes in perception	The Gestalt principle explains why we see faces in clouds.
Gray Matter	Brain tissue containing nerve cell bodies involved in processing	Learning a new skill can increase gray matter in certain brain areas.
Gyrus	A ridge on the brain’s cerebral cortex	The precentral gyrus linked to motor control.
Glia	Non-neuronal brain cells that support and protect neurons	Glia cells help maintain brain function.
Gamma Waves	High-frequency brain waves associated with learning and memory	Meditation can boost gamma wave activity.
Generalization	In psychology, transferring learned responses to similar stimuli	A dog trained to sit to a bell may sit when hearing a chime due to generalization.
Genetic Psychology	Study of psychological development influenced by heredity	Genetic psychology explores how genes shape behavior.
Galvanic Skin Response	Change in skin conductance due to emotions	Lie detectors measure galvanic skin response.
Gustatory Cortex	Brain region responsible for taste perception	Damage to the gustatory cortex affects flavor recognition.
Gamma-Aminobutyric Acid (GABA)	A neurotransmitter that inhibits nervous system activity	GABA helps reduce anxiety and stress.

Conclusion

The glossary of science terms starting with G shows how one letter can cover so many ideas. From the smallest glucose molecule to the largest galaxy, each word is a doorway to deeper understanding. Use this educational science resource as a quick reference or a full learning guide.

Exploring the science vocabulary list pdf for other letters can grow your knowledge even more. Science is a language, and learning its words makes you fluent in the wonders of the universe.