joist

noun

1. any of a number of small, parallel beams of timber, steel, reinforced concrete, etc., for supporting floors, ceilings, or the like.

verb (used with object)

2. to furnish with or fix on joists.

noun

1. a beam made of timber, steel, or reinforced concrete, used in the construction of floors, roofs, etcSee also rolled-steel joist

verb

2. (tr) to construct (a floor, roof, etc) with joists

n.

early 14c. (late 13c. in Anglo-Latin), from Old French giste “beam supporting a bridge” (Modern French gîte), noun use of fem. past participle of gesir “to lie,” from Latin iacere “to lie, rest,” related to iacere “to throw” (see jet (v.)). Notion is of wooden beam on which boards “lie down.”