The Collaborative International Dictionary of English v.0.48:

Proximal \Prox"i*mal\, a.
   1. Toward or nearest, as to a body, or center of motion of
      dependence; proximate.
      [1913 Webster]

   2. (Biol.)
      (a) Situated near the point of attachment or origin; as,
          the proximal part of a limb.
      (b) Of or pertaining to that which is proximal; as, the
          proximal bones of a limb. Opposed to distal.
          [1913 Webster]

WordNet (r) 3.0 (2006):

proximal
    adj 1: situated nearest to point of attachment or origin; "the
           proximal end of a bone" [ant: distal]