| Abbreviation | Designation | |
|---|---|---|
| AB | Appenzeller Bahnen (German) | railway company |
| AB | Ausführungsbestimmungen (German) | legislation / regulation |
| AB | 1. und 2. Klasse (German) | classification |
| SE-AB | Stockholm (län), Stockholms län (Swedish) | country code |
| AB | Ammerländer Busverkehr, AB Ammerländer Busverkehr GmbH (German) | transport company |
| AB | aktiebolag (Swedish) joint-stock company | organization |
| AB | Aschaffenburg Hbf, Stadt Aschaffenburg (German) | fare point / vehicle registration plate |
| Ab | Arbrå (Swedish) | station code |
| Åb | Åsensbruk (Swedish) | station code |
| AB | Angeln-Bahn (German) | railway company |
| AB | Appenzeller Bahn (1885-1988) (German) | railway company |
| AB | Appenzeller Bahnen (1988-2006) (German) | railway company |
| Ab | Abnahmebeamter (German) | profession |