personal identification number vs PIN

personal identification number and PIN both are nouns.

Word	Noun	Adjective	Verb	Adverb
personal identification number	Yes	No	No	No
PIN	Yes	No	No	No

As nouns, personal identification number and PIN are synonyms defined as:

personal identification number and PIN: a number you choose and use to gain access to various accounts

Other synonyms of personal identification number include PIN number.

personal identification number (noun)	PIN (noun)
a number you choose and use to gain access to various accounts	a number you choose and use to gain access to various accounts