Joist (?), n. [OE. giste, OF. giste, F. gite, fr. gesir to lie, F. g'esir. See Gist.] Arch.
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.
© Webster 1913.
Joist, v. t. [imp. & p. p. Joisted; p. pr. & vb. n. Joisting.]
To fit or furnish with joists.
Johnson.
© Webster 1913.