a father:

abbreviation for per annum (= each year):

[ C ] UK abbreviation for personal assistant: someone whose job is helping someone in a higher position, especially by writing letters, arranging meetings, and making phone calls:

US [ C ] UK abbreviation for physician assistant

[ C usually singular ] also PA system abbreviation for public address system (= equipment for making sound, especially someone's voice, louder in a public place):

[ C ] specialized medical abbreviation for pulmonary artery (= the artery that carries dexogygenated blood from the heart to the lungs)

written abbreviation for the US state of Pennsylvania: used in addresses