dad vs pappa

dad and pappa both are nouns.

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

As nouns, dad and pappa are synonyms defined as:

dad and pappa: an informal term for a father; probably derived from baby talk

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

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