Family members left in oven (4)
I believe the answer is:
kiln
'oven' is the definition.
(I know that kiln is a type of oven)
'family members left in' is the wordplay.
'family members' becomes 'kin' (kin means one's relations).
'left' becomes 'L' (common abbreviation).
'in' is an insertion indicator.
'kin' enclosing 'l' is 'KILN'.
(Other definitions for kiln that I've seen before include "Industrial oven" , "Hops or pottery cooker?" , "Potter's furnace" , "Oven for firing bricks" , "Kind of oven" .)