pa vs dad

pa and dad both are nouns.

Word	Noun	Adjective	Verb	Adverb
pa	Yes	No	No	No
dad	Yes	No	No	No

As nouns, pa and dad are synonyms defined as:

Other synonyms of pa include dada, daddy, papa, pappa, pop.

pa (noun)	dad (noun)
an informal term for a father; probably derived from baby talk	an informal term for a father; probably derived from baby talk