| Acronym | Meaning |
| GTM | Guatemala (ISO 3166 Trigram) |
| SLK | Slovak Language (ISO 639-2 Code) |
| WHS | (U.S.) Washington Headquarters Services |
| ITER | International Thermonuclear Experimental Reactor |
| LONEOS | Lowell Observatory Near-Earth-Object Search |
| FORTRAN | The IBM Mathematical FORmula TRANslating System (programming Language) |
| CA | Calcium |
| SLV | El Salvador (ISO 3166 Trigram) |
| SH | Serbo-Croatian Language (ISO 639-1 Code) |
| CEPT | Conf?rence Europ?enne Des Administrations Des Postes Et Des T?l?communications (French |