Place in a TV lineup (4)
I believe the answer is:
slot
'place in a tv lineup' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for slot that I've seen before include "Space for inserting coin" , "Scheduled time -- aperture for coins" , "Long narrow slit" , "Hole for money" , "Long narrow opening" .)