thy·rox·ine 
(thī-rŏksēn′, -sĭn) also thy·rox·in (-rŏksĭn)
(thī-rŏksēn′, -sĭn) also thy·rox·in (-rŏksĭn)n. Abbr. T4
An iodine-containing hormone, C15H11I4NO4, produced by the thyroid gland, that increases the rate of cell metabolism and regulates growth. A synthetic form is used in the treatment of thyroid disorders.
[THYR(O)- + OX(Y)- + IN(DOLE).]