Stripped black insect's secretion
I believe the answer is:
lac
'insect's secretion' is the definition.
(I've seen this in another clue)
'stripped black' is the wordplay.
'stripped' says to take the centre.
The middle letters of 'black' are 'LAC'.
(Other definitions for lac that I've seen before include "Red resin secreted by insects" , "Resinous material" , "Resin used to make varnish" , "Resinous insect secretion" , "One hundred thousand" .)