PR vs publicity

PR and publicity both are nouns.

Word	Noun	Adjective	Verb	Adverb
PR	Yes	No	No	No
publicity	Yes	No	No	No

As nouns, publicity is a hypernym of PR; that is, publicity is a word with a broader meaning than PR:

PR: a promotion intended to create goodwill for a person or institution
publicity: a message issued in behalf of some product or cause or idea or person or institution

Other hypernyms of PR include packaging, promo, promotion, promotional material.

PR (noun)	publicity (noun)
a promotion intended to create goodwill for a person or institution	the quality of being open to public view
a self-governing commonwealth associated with the United States occupying the island of Puerto Rico	a message issued in behalf of some product or cause or idea or person or institution