The Collaborative International Dictionary of English v.0.48:
Subclavian \Sub*cla"vi*an\, a. [Pref. sub- + L. clavis a key. See Clavicle.] (Anat.) Situated under the clavicle, or collar bone; as, the subclavian arteries. [1913 Webster]WordNet (r) 3.0 (2006):
subclavian adj 1: situated beneath the clavicle