Source : Webster's Revised Unabridged Dictionary (1913)

Aventail \Av"en*tail\, n. [OF. esventail. Cf. {Ventail}.]
   The movable front to a helmet; the ventail.

Source : WordNet®

aventail
     n : a medieval hood of mail suspended from a basinet to protect
         the head and neck [syn: {camail}, {ventail}]