The Collaborative International Dictionary of English v.0.48:

Carotid \Ca*rot"id\, Carotidal \Ca*rot"id*al\, a. (Anat.)
   Pertaining to, or near, the carotids or one of them; as, the
   carotid gland.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Carotid \Ca*rot"id\, n. [Gr. ?, pl., from ? heavy sleep: cf. F.
   carotide. The early Greeks believed that these arteries in
   some way caused drowsiness.] (Anat.)
   One of the two main arteries of the neck, by which blood is
   conveyed from the aorta to the head.

   Note: [See Illust. of Aorta.]
         [1913 Webster] Carotid

WordNet (r) 3.0 (2006):

carotid
    adj 1: of or relating to either of the two major arteries
           supplying blood to the head and neck