AB
- A-flat (disambiguation)
- A/B (disambiguation)
- AB (game)
- AB (star catalogue)
- AB Airlines
- AB Bank
- AB Groupe
- AB blood
- AB de Villiers
- AB postcode area
- AB toxin
- Ab (Egyptian heart-soul concept)
- Ab (Mandaean month)
- Ab (Semitic)
- Ab (cuneiform)
- Ab (given name)
- Abkhaz language
- Able Seaman (occupation)
- Able Seaman (rank)
- Activision Blizzard
- Adrien Broner
- Adult baby
- Afrikaner Broederbond
- Aggregate base
- Air Berlin
- Airman Basic
- Aitareya Brahmana
- Akademisk Boldklub
- Aktiebolag
- Alabamine
- Albania
- Alberta
- Albite
- Alderson-Broaddus College
- Alfa-Beta Vassilopoulos
- Allan Border
- Allen-Bradley
- AllianceBernstein
- American Bandstand
- American Biograph
- Ammonia borane
- Amyloid beta
- Analecta Bollandiana
- Ancienne Belgique
- Anheuser-Busch
- Antibody
- Antonio Brown
- Anzab-e Olya
- Ap (water)
- ApacheBench
- Appenzell Railways
- Argja Bóltfelag
- Armed boarding steamer
- Aryan Brotherhood
- Aschaffenburg
- Assembly Bill
- At bat
- Av (month)
- Aviron Bayonnais
- BA (disambiguation)
- Bachelor of Arts
- Bonza
- Category of abelian groups
- Halal snack pack
- List of auxiliaries of the United States Navy
- NZR Ab class
- Pirkei Avot
- Rectus abdominis muscle
- S.A. (corporation)
- United States Air Force
- Welsh patronymic