Rapid Exit Taxiway
Rapid Access Taxiway
Commonly referred to over here as RET's and RAT's.
I'm struggling to think of an instance of a Rapid Access Taxiway at a UK airport - although of course all RETs are RATs when the wind is in the opposite direction.
Google doesn't help much: only 63 hits overall for RAT compared to 11,000+ for RET.