Primate's cross and crown (4)
I believe the answer is:
apex
'crown' is the definition.
(thesaurus)
'primate's cross' is the wordplay.
'primate' becomes 'ape' (I've seen this before**).
'cross' becomes 'x'.
'ape'+'x'='APEX'
'and' acts as a link.
(Other definitions for apex that I've seen before include "high-point" , "Cheap fare" , "Top, peak" , "Topmost point" , "Point or summit" .)