Joist

Part of speech: noun (n.)

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.

Part of speech: verb (v.)

To fit or furnish with joists. Johnson.