Drink to fix temperature (4)
I believe the answer is:
pint
'drink' is the definition.
(pint is a unit of liquid volume)
'fix temperature' is the wordplay.
'fix' becomes 'pin' (to pin is to fix in place).
'temperature' becomes 't' (abbreviation).
'pin'+'t'='PINT'
'to' is the link.
(Other definitions for pint that I've seen before include "Unit of beer" , "The working man's drink measure" , "small amount" , "Standard measure of beer or milk" , "Measure of the plain man's alcoholic drink" .)