[tra.chea] n, pl -che.ae also -che.as [ME, fr. ML, fr. LL trachia, fr. Gk tracheia (arteria) rough (artery), fr. fem. of trachys rough] (14c) 1: the main trunk of the system of tubes by which air passes to and from the lungs in vertebrates
2. [NL, fr. ML]: vessel 3b; also: one of its constituent cellular elements 3 [NL]: one of the air-conveying tubules forming the respiratory system of most insects and many other arthropods -- tra.che.al adj