Ab (thing)

(USN Rating) Aviation Boatswain's Mate
Abduction
Able-Bodied
Abort (ITU-T)
Abortion
Accelerated Budget
Access Burst
Accounts Branch
Ada-Based
After-Burner
Air Base
Air Blast
Air Break
Airborne
Airborne Bombing
Airman Basic
Aktiebolag
Alberta (Canada)
All Before
Aneroid Barometer
Answer Back
Army Brigade
Array Bending
Artis Baccularatum (Latin: Bachelor of Arts) University Degree
Assault Breaker
Assumed Benefit (type of qualified retirement plan)
At Bat (baseball, softball)
Atomic Bomberman (game)
Avionics Bay
A Crane Ship
A signal ground
...and what Webby said. :-)