ABC
As easy as "1-2-3?" Well, according to Boeing Library Service's acronym search, it could be a little more complex:

AWACS Brassboard Computer
Absorbing Boundary Condition
Academia Brasileira De Ciencias
Activity-Based Costing
Advance Base Components
Advance Baseline Configuration
Advanced Ballistics Concepts
Advanced Biomedical Capsule
Advancing Blade Concept
American Bowling Congress
American British Canadian
American Broadcasting Company
American-British Conversation
Anti-Birdcager
Anti-Skid Braketemp Controller
Approach By Concept
Argentina, Brazil, and Chile
Atomic, Biological, Chemical (Warfare)
Audit Bureau of Circulation
Australian Broadcasting Corporation