Fix that a late don might be in? (6)
I believe the answer is:
cement
'fix' is the definition.
(I know that cement is a type of fix)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cement that I've seen before include "binder" , "Building material to bind things" , "Stick together - substance used by a builder" , "material for bonding" , "Bind firmly" .)