Sketches include vessel (5)
I believe the answer is:
ketch
'vessel' is the definition.
(ketch is a kind of vessel)
'sketches include' is the wordplay.
'include' indicates a hidden word.
'KETCH' can be found hidden inside 'sketches'.
(Other definitions for ketch that I've seen before include "Jack" , "Two-masted sailing boat" , "Two-masted sailing vessel" , "Small two-master sailing vessel" , "2-masted boat" .)