'p.a.' definitions:
Definition of 'p.a.'
From: WordNet
adverb
By the year; every year (usually with reference to a sum of money paid or received); "he earned $100,000 per annum"; "we issue six volumes per annum" [syn: per annum, p.a., per year, each year, annually]
noun
An electronic amplification system used as a communication system in public areas [syn: public address system, P.A. system, PA system, P.A., PA]