Cook for example is an officer (7)
I believe the answer is:
captain
I believe this is a double definition.
'cook for example' is the first definition.
(Captain James Cook)
'an officer' is the second definition.
(captain is a kind of officer)
'is' acts as a link.
(Other definitions for captain that I've seen before include "American police officer" , "eg Hook, Cook" , "Skip" , "eg Hornblower" , "US policeman" .)