/truy'uy oh'doh thuy"reuh neen', -uy od'oh-/ , n.
1. Biochem. a thyroid hormone, C 15 H 12 I 3 NO 4 , similar to thyroxine but several times more potent.
2. Pharm. a preparation of this hormone, used in treating hypothyroidism. Abbr.: T 3
[ 1950-55; TRI- + IODO- + thyronine (perh. deriv., with -ONE, of THYROXINE) ]