Joist /(joist)/

1. A piece of timber laid horizontally, or nearly so, to which the planks of the floor, or the laths or furring strips of a ceiling, are nailed; -- called, according to its position or use, binding joist, bridging joist, ceiling joist, trimming joist, etc. See Illust. of Double-framed floor, under Double, a. (Arch.)

imp. & p. p. Joisted; p. pr. & vb. n. Joisting

1. To fit or furnish with joists.