| Category | Contains the number of abbreviations |
|---|---|
| Air Force | 219 |
| Alliances | 1323 |
| Authorities | 609 |
| Bureaus | 493 |
| Civic & Municipal | 456 |
| Commerce | 333 |
| Council | 2766 |
| Employment | 1164 |
| Energy | 2207 |
| Environmental | 4102 |
| FBI Files | 521 |
| FDA | 3962 |
| Federation | 939 |
| Fire Departments | 435 |
| Immigration | 256 |
| Institutes | 5632 |
| Law & Legal | 7507 |
| Legislation | 666 |
| Military | 31683 |
| NASA | 11598 |
| Navy | 6091 |
| Nazi Regime | 152 |
| Planning | 1055 |
| Police | 2727 |
| Politics | 2530 |
| State & Local | 4621 |
| Suppliers | 298 |
| Transportation | 7855 |
| United Nations | 1337 |
| US Government | 6615 |