Welt

n. [Scot. welt, A-S. weltan, to roll, or more probably from W. gwald, a hem, a welt, gwaldu, to welt or to hem, from gwal, a fence or wall, gwaliaw, to inclose.] That which, being folded or brought round, serves to guard, strengthen, or adorn something; as, (a.) A small cord covered with cloth and sewed on a seam or border to strengthen it; an edge of cloth folded on itself, usually over a cord, and sewed down. (b.) A hem, border, or fringe. [Obs. or rare.] (c.) A narrow strip of leather around a shoe, between the upper leather and sole. (d.) (Steam-boilers.) A batten riveted over the seam between two plates.

Welt-joint, a joint made with a welt, in distinction from one made by overlapping the plates.

To welter or wither; to wilt. [Rare.]