Combine, blend (3)
I believe the answer is:
mix
This clue is a double definition.
'combine' is the first definition.
(mix is a kind of combine)
'blend' is the second definition.
(I know that blend is a kind of mix)
(Other definitions for mix that I've seen before include "Mingle, blend" , "Get on" , "= 1,009 (L.)" , "Blend or socialise" , "Blend together" .)