staircase vs building

staircase and building both are nouns.

Word	Noun	Adjective	Verb	Adverb
staircase	Yes	No	No	No
building	Yes	No	No	No

staircase (noun)	building (noun)
a way of access (upward and downward) consisting of a set of steps	the act of constructing something
	the commercial activity involved in repairing old structures or constructing new ones
	a structure that has a roof and walls and stands more or less permanently in one place
	the occupants of a building