P
— Noun
– English
～ the 16th letter of the Roman alphabet
P
— Noun
– English
～ a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms
p-n junction
— Noun
– English
～ the junction between a p-type semiconductor and an n-type semiconductor; "a p-n junction has marked rectifying characteristics"