trichodal,a.Zool.|trɪˈkəʊdəl| [f.Gr. τριχώδης hair-like (f. θρίξ, τριχ- hair: see -ode1) + -al1.] Extremely thin: applied to a sponge-spicule. 1888Sollas in Challenger Rep. XXV. p. lviii, Both the rhabdus and the style may..be..immeasurably thin (trichodal, τριχώδης, hair-like).