[thy.roid] also thy.roi.dal adj [NL thyroides, fr. Gk thyreoeides shield-shaped, thyroid, fr. thyreos shield shaped like a door, fr. thyra door--more at door] (ca. 1741) 1 a: of, relating to, or being a large bilobed endocrine gland of craniate vertebrates lying at the base of the neck and producing esp. the hormones thyroxine and triiodothyronine b: suggestive of a disordered thyroid "a ~ personality"
2: of, relating to, or being the chief cartilage of the larynx
[2]thyroid n (1840) 1: a thyroid gland or cartilage; also: a part (as an artery or nerve) associated with either of these
2: a preparation of mammalian thyroid gland used in treating thyroid disorders