PR vs public relations

PR and public relations both are nouns.

Word	Noun	Adjective	Verb	Adverb
PR	Yes	No	No	No
public relations	Yes	No	No	No

As nouns, PR and public relations are synonyms defined as:

PR and public relations: a promotion intended to create goodwill for a person or institution

PR (noun)	public relations (noun)
a promotion intended to create goodwill for a person or institution	a promotion intended to create goodwill for a person or institution
a self-governing commonwealth associated with the United States occupying the island of Puerto Rico