Trio's playing beside small lake that has a spit (10)
I believe the answer is:
rotisserie
'that has a spit' is the definition.
(I know this)
'trio's playing beside small lake' is the wordplay.
'playing' is an anagram indicator.
'beside' is a charade indicator (letters next to each other) (I've seen this in other clues).
'small' becomes 's' (abbreviation - e.g. clothes size).
'lake' becomes 'erie' (Lake Erie is one of the Canadian/US 'Great Lakes').
'trios' with letters rearranged gives 'rotis'.
'rotis'+'s'+'erie'='ROTISSERIE'
(Other definitions for rotisserie that I've seen before include "Rotating spit for roasting" , "it can get pretty hot" , "Cooking appliance with spit" , "Restaurant; rotating spit" , "something used for cooking" .)