Part of B.Y.O.B. (4)
'part of byob' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for own that I've seen before include "Keep" , "Control" , "Acknowledge" , "Posses" , "Possess or confess" .)
(Other definitions for your that I've seen before include "See 14" , "-- Honour; -- Majesty" , "See 5" , "Second person's" , "-- Majesty; -- Grace" .)