Definition of thyroid in English:


Syllabification: thy·roid
Pronunciation: /ˈTHīˌroid


  • 1 (also thyroid gland) A large ductless gland in the neck that secretes hormones regulating growth and development through the rate of metabolism.
    More example sentences
    • Thyroid medicine can replace the hormone your thyroid gland usually makes.
    • When your thyroid gland produces too much of the hormone thyroxine, you develop hyperthyroidism.
    • This happens because the thyroid gland is not functioning properly.
  • 1.1An extract prepared from the thyroid gland of animals and used in treating deficiency of thyroid hormones.
    More example sentences
    • He was horrified that I had been taking dried animal thyroid and put me on Synthroid.
    • Any patient with suspected myxedema coma should be treated presumptively with thyroid hormone.
    • A month later, after he started taking thyroid extract, the life of the patient had been transformed.
  • 2 (also thyroid cartilage) A large cartilage of the larynx, a projection of which forms the Adam’s apple in humans.
    More example sentences
    • The epiglottis is a flap-like cartilage connected to the thyroid cartilage.
    • The corpsman then palpated the thyroid cartilage and found the ‘Adam's apple’ or laryngeal prominence.
    • The hyoid bone, thyroid cartilage, and cricoid cartilages are located within the central portion of the neck.


early 18th century (as an adjective): from Greek (khondros) thureoeidēs 'shield-shaped (cartilage)', from thureos 'oblong shield'.

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