atmospheric pressure vs air pressure

atmospheric pressure and air pressure both are nouns.

Word	Noun	Adjective	Verb	Adverb
atmospheric pressure	Yes	No	No	No
air pressure	Yes	No	No	No

As nouns, atmospheric pressure and air pressure are synonyms defined as:

atmospheric pressure and air pressure: the pressure exerted by the atmosphere

Other synonyms of atmospheric pressure include pressure.

atmospheric pressure (noun)	air pressure (noun)
the pressure exerted by the atmosphere	the pressure exerted by the atmosphere