The Collaborative International Dictionary of English v.0.48:

Arterial \Ar*te"ri*al\, a. [Cf. F. art['e]riel.]
   1. Of or pertaining to an artery, or the arteries; as,
      arterial action; the arterial system.
      [1913 Webster]

   2. Of or pertaining to a main channel (resembling an artery),
      as a river, canal, or railroad.
      [1913 Webster]

   Arterial blood, blood which has been changed and vitalized
      (arterialized) during passage through the lungs.
      [1913 Webster]

WordNet (r) 3.0 (2006):

arterial blood
    n 1: blood found in arteries; "except for the pulmonary artery
         the arterial blood is rich in oxygen"