standard pressure vs standard atmosphere

standard pressure and standard atmosphere both are nouns.

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

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

standard pressure and standard atmosphere: 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 pressure include atm, atmosphere.

standard pressure (noun)	standard atmosphere (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