Source : Webster's Revised Unabridged Dictionary (1913)

Thyroid \Thy"roid\, a. [Gr. ? shield-shaped; ? a large, oblong
   shield (from ? a door) + ? form: cf. F. thyro["i]de,
   thyr['e]o["i]de.]
   1. Shaped like an oblong shield; shield-shaped; as, the
      thyroid cartilage.

   2. (Anat.) Of or pertaining to the thyroid body, thyroid
      cartilage, or thyroid artery; thyroideal.

   {Thyroid cartilage}. See under {Larynx}.

   {Thyroid body}, or {Thyroid gland} (Anat.), a glandlike but
      ductless body, or pair of bodies, of unknown function, in
      the floor of the mouth or the region of the larynx. In man
      and most mammals it is a highly vascular organ, partly
      surrounding the base of the larynx and the upper part of
      the trachea.

Source : WordNet®

thyroid
     adj 1: of or relating to the thyroid gland; "thyroid deficiency";
            "thyroidal uptake" [syn: {thyroidal}]
     2: suggestive of a thyroid disorder; "thyroid personality"

thyroid
     n : located near the base of the neck [syn: {thyroid gland}]