standard atmosphere vs atm

standard atmosphere and atm both are nouns.

Word	Noun	Adjective	Verb	Adverb
standard atmosphere	Yes	No	No	No
atm	Yes	No	No	No

As nouns, standard atmosphere and atm are synonyms defined as:

standard atmosphere and atm: a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade

Other synonyms of standard atmosphere include atmosphere, standard pressure.

standard atmosphere (noun)	atm (noun)
a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade	a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade