Mortise and _____ (5)
I believe the answer is:
tenon
(Other definitions for tenon that I've seen before include "Part of woodworking joint" , "Join" , "joiner" , "One projecting" , "Shaped end of piece of wood for slotting into a hole." .)
I believe the answer is:
tenon
(Other definitions for tenon that I've seen before include "Part of woodworking joint" , "Join" , "joiner" , "One projecting" , "Shaped end of piece of wood for slotting into a hole." .)