Rocks at the bar (3)
I believe the answer is:
ice
'rocks at the bar' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ice that I've seen before include "It's cold and slippy" , "To put in a drink or slide on" , "Diamonds, colloquially" , "Skating surface" , "Some number" .)