Glue in suitable measure (4)
I believe the answer is:
size
This clue could be a double definition.
'glue' is the first definition.
(I've seen this before)
'suitable measure' is the second definition.
'size' can be an answer for 'measure' (size is a kind of measure). I am unsure of the 'suitable' bit.
'in' is the link.
Can you help me to learn more?
(Other definitions for size that I've seen before include "Standard measurement" , "Magnitude; glue" , "stiffener" , "Degree of largeness" , "Extent; a sealant" .)