flight of stairs vs flight of steps

flight of stairs and flight of steps both are nouns.

Word	Noun	Adjective	Verb	Adverb
flight of stairs	Yes	No	No	No
flight of steps	Yes	No	No	No

As nouns, flight of stairs and flight of steps are synonyms defined as:

flight of stairs and flight of steps: a stairway (set of steps) between one floor or landing and the next

Other synonyms of flight of stairs include flight.

flight of stairs (noun)	flight of steps (noun)
a stairway (set of steps) between one floor or landing and the next	a stairway (set of steps) between one floor or landing and the next