Number in figures on gate (4)
I believe the answer is:
song
'number' is the definition.
(I've seen this in another clue)
'in figures on gate' is the wordplay.
'in' says the answer is hidden in the clue.
'SONG' is hidden in the letters of 'figures on gate'.
(Other definitions for song that I've seen before include "See 17" , "Words set to music" , "Musical rendition" , "Musical number" , "You work best when on this" .)