Display on stone step (5)
I believe the answer is:
stair
'step' is the definition.
(a single step in a staircase)
'display on stone' is the wordplay.
'display' becomes 'air' (air can mean to display or show something).
'on' says to put letters next to each other.
'stone' becomes 'st' (abbreviation).
'air' put after 'st' is 'STAIR'.
(Other definitions for stair that I've seen before include "Indoor step" , "Rising step" , "something of a case" , "one on the way up" , "Tarsi (anag)" .)