Part of a pot (4)
I believe the answer is:
ante
'part of a pot' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ante that I've seen before include "Fixed stake" , "Poker pot starter" , "Pay" , "Initial stake in a poker game" , "Stake put up by a poker-player before receiving cards" .)