The Collaborative International Dictionary of English v.0.48:

Distal \Dis"tal\, a. [From Distant.] (Physiol.)
   (a) Remote from the point of attachment or origin; as, the
       distal end of a bone or muscle; -- opposed to proximal.
   (b) Pertaining to that which is distal; as, the distal
       tuberosities of a bone.
       [1913 Webster]

WordNet (r) 3.0 (2006):

distal
    adj 1: situated farthest from point of attachment or origin, as
           of a limb or bone [ant: proximal]
    2: directed away from the midline or mesial plane of the body
       [ant: mesial]