Sip drop of sherry in gallery (5)
I believe the answer is:
taste
'sip' is the definition.
(thesaurus)
'drop of sherry in gallery' is the wordplay.
'drop of' indicates taking the first letters.
'in' is an insertion indicator.
'gallery' becomes 'tate' (I've seen this before).
The first letter of 'sherry' is 's'.
's' placed within 'tate' is 'TASTE'.
(Other definitions for taste that I've seen before include "Sample, savour" , "Take mouthful" , "Sensation in the mouth caused by food" , "A sense; briefly sample" , "eat only the smallest amount" .)