stairs; stairway; staircase

stage; step; phase

level; rank; grade; gradation

order

stairs

second floor; upstairs

Common noun; Noun, used as a suffix

storey; story; floor

Common noun

stairs

Common noun; Noun, used as a suffix

stage (in chronostratigraphy)

Counter

counter for storeys and floors of a building

first floor; ground floor

one floor; one storey

one rank

(social) class

rank; grade

third floor

to go up the stairs; to climb the stairs

class; level; stratum; layer; hierarchy

lower floor; downstairs

bottom of the stairs; foot of the stairs