| Abbreviation | Definition |
|---|---|
| GPCR | Gas Phase Chemical Reduction |
| GPCRS | Gas Phase Chemical Reduction System |
| GPS | Gold Plated Silver |
| GR | General Radiation |
| GR | Glufosinate Resistant |
| GR | Guaranteed Reagent |
| GRASS | Science term to calculate the volume, mass, or density. G=Given R=Required A=Analysis S=Solution S=Statement |
| GRD | Genealogical Research Directory |
| GRIM | Glass Refractive Index Measurement |
| GRO | Gasoline Range Organics |
| GS | Gold And Silver |
| GSC | Green Sustainable Chemistry |
| GSO | General Spin Orbital |
| GSSG | Glutathione-S-S-Glutathione |
| GST | Germanium-Antimony-Tellurium (GeSbTe) |
| GSX | Granular Salmeterol Xinafoate |
| GT | Glass Tubular |
| GTD | Glyoxal Trimeric Dihydrate |
| GTL | Gas To Liquid |
| GTN | Glyceryl TriNitrate |