| GCI | General Cognitive Index |
|---|---|
| GCRC | General Clinical Research Center [of NIH] |
| GCS | general clinical services; Gianotti-Crosti syndrome; Glasgow Coma Scale; glucocorticosteroid; glutam... |
| GCT | general care and treatment; germ-cell tumor; giant cell thyroiditis; giant cell tumor |
| GCWM | General Conference on Weights and Measures |