Merriam-Webster Collegiate Dictionary - trachea

 noun  (plural ~e; also -cheas or -chea)  Etymology: Middle English, from Medieval Latin, from Late Latin trachia, from Greek tracheia (arteria) rough (artery), from feminine of trachys rough  Date: 14th century  1. the main trunk of the system of tubes by which air passes to and from the lungs in vertebrates  2. New Latin, from Medieval Latin vessel 3b; also one of its constituent cellular elements  3. New Latin one of the air-conveying tubules forming the respiratory system of most insects and many other arthropods  • ~l adjective