| Abbreviation | Definition |
|---|---|
| FTGA | Fission Track Grain Age |
| GA | Growth Accelerated |
| GC | Gardening Club |
| GCCA | Greater Chicago Cichld Association |
| GCH | Garden Club of Houston |
| GFKV | Grapevine Fleck Virus |
| GG | Geissler Greenhouse |
| GI | Guano Infested |
| GIOC | Green Infrastructure Ontario Coalition |
| GL | Green Luminescence |
| GLOX | Galactose OXidase |
| GLW | Garlic Leaves, Wild |
| GMI | Grow Me Instead |
| GN | Grass Nibbler |
| GOM | Gardens Of Memories |
| GRBG | Garden Route Botanical Garden (South Africa) |
| GRIN | Germplasm Resources Information Network |
| GRWR | Graft to Recipient Weight Ratio |
| GSBI | Gloucestershire Society for Botanical Illustration |
| GSOB | Gold-Spotted Oak Borer |