[ trahy-ahy-oh-doh-thahy-ruh-neen, -ahy-od-oh- ]
/ ˌtraɪ aɪˌoʊ doʊˈθaɪ rəˌnin, -aɪˌɒd oʊ- /


Biochemistry. a thyroid hormone, C15H12I3NO4, similar to thyroxine but several times more potent.
Pharmacology. a preparation of this hormone, used in treating hypothyroidism. Abbreviation: T3


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Origin of triiodothyronine

1950–55; tri- + iodo- + thyronine (perhaps derivative, with -one, of thyroxine)

Words nearby triiodothyronine Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for triiodothyronine

/ (ˌtraɪaɪˌəʊdəʊˈθaɪrəˌniːn) /


an amino acid hormone that contains iodine and is secreted by the thyroid gland with thyroxine, to which it has a similar action. Formula: C 15 H 12 I 3 NO 4

Word Origin for triiodothyronine

C20: from tri- + iodo- + thyro- + -ine 2
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012