Flap less than the whole wing (3)
I believe the answer is:
tab
This clue could be a double definition.
'flap less than' is the first definition.
'tab' can be an answer for 'flap' (both can mean a small piece of material). I'm not certain of the 'less than' bit.
'whole wing' is the second definition.
'tab' can be an answer for 'wing' (thesaurus). I am not certain of the 'whole' bit.
'the' is the link.
Can you help me to learn more?
(Other definitions for tab that I've seen before include "Bar tally; small flap" , "Marker" , "Till bill" , "Ring pull" , "ticket" .)