Party given by cape medic (3)
I believe the answer is:
doc
'medic' is the definition.
(doctor)
'party given by cape' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'given by' is a charade indicator (letters next to each other).
'cape' becomes 'c' (abbreviation used on maps).
'do'+'c'='DOC'
(Other definitions for doc that I've seen before include "GP (informal)" , "bones" , "Medical practitioner (abbr)" , "Fox perhaps" , "Medic (familiar)" .)