IPO vs initial offering

IPO and initial offering both are nouns.

Word	Noun	Adjective	Verb	Adverb
IPO	Yes	No	No	No
initial offering	Yes	No	No	No

As nouns, IPO and initial offering are synonyms defined as:

IPO and initial offering: a corporation's first offer to sell stock to the public

Other synonyms of IPO include initial public offering.

IPO (noun)	initial offering (noun)
a corporation's first offer to sell stock to the public	a corporation's first offer to sell stock to the public