Ready, stand on the seat (6)
I believe the answer is:
settee
'the seat' is the definition.
(settee is a kind of seat)
'ready stand on' is the wordplay.
'ready' becomes 'set' ('set' can be similar in meaning to 'ready').
'stand' becomes 'tee' (I've seen this before).
'on' is a charade indicator (letters next to each other).
'set'+'tee'='SETTEE'
(Other definitions for settee that I've seen before include "solver, might you say?" , "Piece of furniture" , "Chesterfield" , "Item of furniture" , "Get a seat" .)