China 
Africa 
- Graphics library
- Graphics pipeline
- Graphics software
- Graphics tablets
- Graphite
- Graphite intercalation compound
- Graphite oxide
- Graphite-moderated reactors
- Graphitic carbon nitride
- Graphitization
- Graphplan
- Graphs
- Graphviz
- Graphyne
- Grapple
- Grashof number
- Grasp
- Grassland degradation
- Grassmannians
- Grate firing
- Grating light valve
- Grating lobes
- Gratings
- Graupel
- Gravel
- Gravel pit
- Gravel roads
- Gravimeters
- Gravimetric analysis
- Gravimetry
- Gravitational acceleration
- Gravitational constant
- Gravitational field
- Gravitational microlensing
- Gravitational potential
- Gravitational wave background
- Gravitational waves
- Gravity
- Gravity anomaly
- Gravity assist
- Gravity currents
- Gravity dams
- Gravity gradiometry
- Gravity of earth
- Gravity separation
- Gravity sewer
- Gravity turn
- Gravity waves
- Gravity-based structures
- Gray
- Gray code
- Gray iron
- Grayscale
- Grazing incidence small angle x-ray scattering
- Grease
- Grease gun
- Grease trap
- Great Deluge Algorithm
- Great Dyke
- Great Green Wall
- Great Lakes Water Quality Agreement
- Great Pacific Garbage Patch
- Great arteries
- Great circle route
- Great circles
- Great vessel
- Great-circle distance
- Greater trochanter
- Greater tubercle
- Greedy algorithms
- Greedy randomized adaptive search procedure
- Green Building Council
- Green Building XML
- Green Star
- Green belt
- Green body
- Green brands
- Green building
- Green building certification systems
- Green buildings
- Green certificates
- Green chemistry
- Green chemistry metrics
- Green computing
- Green dot
- Green economy
- Green engineering
- Green hydrogen
- Green infrastructure
- Green manure
- Green nanotechnology
- Green recovery
- Green roofs
- Green rust
- Green solvent
- Green strength
- Green technology
- Green urbanism
- Green vehicle
- Green walls
- Green waste
- Green wave
- Green's function
- Green's theorem
- Greenhouse effect
- Greenhouse gas emissions
- Greenhouse gas inventory
- Greenhouse gases
- Greenland ice sheet
- Greenockite
- Greensand
- Greenschist
- Greenstick fractures
- Greenstone belts
- Greenways
- Greenwich
- Greigite
- Greisen
- Grey matter
- Grey relational analysis
- Grey system theory
- Greywacke
- Greywater
- Grid
- Grid balancing
- Grid cells
- Grid code
- Grid computing
- Grid energy storage
- Grid file
- Grid fins
- Grid graph
- Grid parity
- Grid reference
- Grid-connected
- Grid-tie inverter
- GridFTP
- Gridshells
- Grignard reaction
- Grignard reagents
- Grilles
- Grinding
- Grinding machine
- Grinding wheels
- Grindstones
- Griseofulvin
- Gritstone
- GroEL
- Grog
- Groin