1. The thyroid gland.
2. The thyroid cartilage.
3. A dried, powdered preparation of the thyroid gland of certain domestic animals, used in treatment of hypothyroid conditions.
4. An artery, vein, nerve, or other part associated with the thyroid gland or thyroid cartilage.
[Greek thureoeidēs : thureos, oblong shield (from thurā, door; see dhwer- in the Appendix of Indo-European roots) + -oeidēs, -oid.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.