thyroid, n. & adj.
--n. (in full thyroid gland)
1 a large ductless gland in the neck of vertebrates secreting a hormone which regulates growth and development through the rate of metabolism.
2 an extract prepared from the thyroid gland of animals and used in treating goitre and cretinism etc.
--adj. Anat. & Zool.
1 connected with the thyroid cartilage (thyroid artery).
2 shield-shaped.
thyroid cartilage a large cartilage of the larynx, the projection of which in man forms the Adam's apple.
obs.F thyroide or mod.L thyroides, irreg. f. Gk thureoeides f. thureos oblong shield