staircase vs stairway

staircase and stairway both are nouns.

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

As nouns, staircase and stairway are synonyms defined as:

staircase and stairway: a way of access (upward and downward) consisting of a set of steps

staircase (noun)	stairway (noun)
a way of access (upward and downward) consisting of a set of steps	a way of access (upward and downward) consisting of a set of steps