Blend; combine (10)
I believe the answer is:
amalgamate
This clue is a double definition.
'blend' is the first definition.
(I've seen this in another clue)
'combine' is the second definition.
(I know that combine is a more specific form of the action amalgamate)
(Other definitions for amalgamate that I've seen before include "Mix" , "Join" , "get together" , "Compound" , "Merge" .)