Record temperature, then take off (4)
I believe the answer is:
tape
'record' is the definition.
(I know that record can be written as tape)
'temperature then take off' is the wordplay.
'temperature' becomes 't' (abbreviation).
'then' is a charade indicator (letters next to each other).
'take off' becomes 'ape' (both can mean to imitate).
't'+'ape'='TAPE'
(Other definitions for tape that I've seen before include "that may be red" , "that race winner may break" , "Race winning line; record" , "Race finishing-line" , "Sticky strip" .)