The Collaborative International Dictionary of English v.0.48:

Axillary \Ax"il*la*ry\ ([a^]ks"[i^]l*l[asl]*r[y^]), a. [See
   Axil.]
   1. (Anat.) Of or pertaining to the axilla or armpit; as,
      axillary gland, artery, nerve.
      [1913 Webster]

   2. (Bot.) Situated in, or rising from, an axil; of or
      pertaining to an axil. "Axillary buds." --Gray.
      [1913 Webster]

WordNet (r) 3.0 (2006):

axillary
    adj 1: of or relating to the axil [syn: axillary, alar]
    2: of or relating to the armpit; "axillary gland"