Source : Webster's Revised Unabridged Dictionary (1913)

Axil \Ax"il\, n. [L. axilla. Cf. {Axle}.] (Bot.)
   The angle or point of divergence between the upper side of a
   branch, leaf, or petiole, and the stem or branch from which
   it springs. --Gray.

Source : WordNet®

axil
     n : the upper angle between an axis and an offshoot such as a
         branch or leafstalk