What does "gusset" mean?

Gusset: Anything resembling a gusset in a garment; as: (a) (Armor) A small piece of chain mail at the openings of the joints beneath the arms. (b) (Mach.) A kind of bracket, or angular piece of iron, fastened in the angles of a structure to give strength or stiffness; esp., the part joining the barrel and the fire box of a locomotive boiler.

Additional senses

  1. 2.(Her.) An abatement or mark of dishonor in a coat of arms, resembling a gusset.

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