Word Origin & History
c.1400, "lattice, grating," from O.Fr. trelis, originally "sackcloth," from V.L. *trilicius, from L. trilicis, gen. of trilix "having three threads, triple-twilled," from tri- three + licium "thread." Cognate with Gk. trimitos. Sense extended in O.Fr. to things "woven" of iron, etc., which brought on
infl. of O.Fr. treille "vine trellis," perhaps from L. trichila "bower, arbor," which is apparently from L. triclinium "couch extending round three sides of a table" (for reclining on at meals). Meaning "lattice used to support growing vines" is from 1513.