Ace location in boulevard (6)
I believe the answer is:
avenue
'boulevard' is the definition.
(I know that boulevard can be written as avenue)
'ace location' is the wordplay.
I cannot really understand how this works, but
'ace' could be 'a' (abbreviation) and 'a' is found within the answer.
'location' could be 'venue' (venue is a kind of location) and 'venue' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for avenue that I've seen before include "Way of approach" , "A line of approach" , "Wide and handsome street" , "Entrance passage" , "Wide street or road as in New York" .)