1. [Brit] Advisory, Conciliation and Arbitration Service 
2. Airborne Collision Avoidance System

Encyclopedia: ACAS

• thighbone
• thigmotaxis
• thill
• thimble
• thimble-shaped
• thimbleberry
• thimbleful
• thimblerig
• thimblerigger
• thimbleweed
• thimerosal
• thin
• thin air
• thin out
• thin person
• thin-bodied
• thin-leaved bilberry
• thin-leaved stringybark
• thin-shelled
• thin-shelled mussel
• thin-skinned
• thine
• thing
• thing-in-itself
• thingamabob