p vs P

p and P both are nouns.

Word	Noun	Adjective	Verb	Adverb
p	Yes	No	No	No
P	Yes	No	No	No

As nouns, p and P are synonyms defined as:

p (noun)	P (noun)
the 16th letter of the Roman alphabet	the 16th letter of the Roman alphabet
	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