What is the meaning of Gusset?

A small piece of cloth inserted in a garment, for the purpose of strengthening some part or giving it a tapering enlargement cf. godet.

A gousset, a piece of mail providing protection where armor plates meet.

A kind of bracket, or angular part, 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.

An ordinary on a coat of arms, resembling a gusset .

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.

To make with a gusset; to sew a gusset into.

Source: wiktionary.org