Bat lost label (3)
I believe the answer is:
tab
'label' is the definition.
(I've seen this before)
'bat lost' is the wordplay.
'lost' is an anagram indicator.
'bat' anagrammed gives 'TAB'.
(Other definitions for tab that I've seen before include "Running bar bill" , "Tally at bar (colloq.)" , "Flap; meal bill" , "Tally of orders in bar" , "Ring pull" .)