usage: a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
3. protactinium, protoactinium, Pa, atomic number 91, metallic element, metal
usage: a unit of pressure equal to one newton per square meter
4. pascal, Pa, pressure unit
usage: a Mid-Atlantic state; one of the original 13 colonies
Adverb
1. per annum, p.a., per year, each year, annually
usage: 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"