gusset

Etymology

From Middle English gusset, gysset, from Old French gosset, gousset (“the hollow of the armpit”).

noun

1. A small piece of cloth inserted in a garment, for the purpose of strengthening some part or giving it a tapering enlargement cf. godet.
2. A gousset, a piece of mail providing protection where armor plates meet.
3. (machinery) A kind of bracket, or angular piece of iron, fastened in the angles of a structure to give strength or stiffness; especially, the part joining the barrel and the fire box of a locomotive boiler.
4. (heraldry) An ordinary on a coat of arms, resembling a gusset (see usage notes).
5. (roofing) A large flat metal piece wider than the valley to help prevent build-up at the base of the valley, either from debris or ice dam formations.

verb

1. (transitive) To make with a gusset; to sew a gusset into.