Measure monarch, for example (5)
I believe the answer is:
ruler
I believe this is a double definition.
'measure' is the first definition.
(I know that ruler is a type of measure)
'monarch for example' is the second definition.
(monarch is a kind of ruler)
(Other definitions for ruler that I've seen before include "Commander" , "Queen, say" , "King, president etc." , "Monarch - drafting tool" , "Measuring rod; governor" .)