the main hormone produced by the thyroid gland, acting to increase metabolic rate and so regulating growth and development.
An iodine-containing amino acid; chemical formula: C15H11NO4I4
Origin:
early 20th century: from thyroid+ ox- 'oxygen' + in from indole (because of an early misunderstanding of its chemical structure), altered by substitution of -ine4
thyroxine in other Oxford dictionaries
Definition of thyroxine in the US English dictionary
