- Gideon Planish
- gable window
- Giemsa staining
- Giemsa-Romanowsky stain
- Giemsa-Romanowsky staining
- Giengen on the Brenz
- greedy guts
- Giesel
- galvie flu
- Giessen
- GIF file
- garish green
- Gig City
- giga...
- gigaampere , GA
- gigabecquerel , GBq
- gigaelectron volt, GeV
- gigagram , Gg
- gigagramme , Gg
- gigahenry , GH
- gigacycle , Gc
- gigahertz , GHz
- gigajoule , GJ
- gigameter , Gm
- gigametre , Gm
- Giant
- giant balloon
- giant telescope
- gigantoblasts
- gigapascal , GPa
- gigatesla , GT
- gigavolt , GV
- gigawatt , GW
- gigli
- Gigli's operation
