/thuy rok"seen, -sin/ , n.
1. Biochem. the thyroid gland hormone that regulates the metabolic rate of the body.
2. Pharm. a commercial form of this compound, obtained from the thyroid glands of animals or synthesized, used in the treatment of hypothyroidism. Symbol.: T 4
Also, thyroxin /thuy rok"sin/ .
[ 1915-20; THYR- + OX- + IN(DOL)E (orig. thought to be a chemical component) ]