Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
A secretion that is produced by an endocrine gland and discharged directly into the bloodstream; a hormone.
Etymology: L, internus, inward, secernere, to separate
a type of secretion in which substances pass directly from a gland into the bloodstream.
An outdated term for the secretion of an endocrine gland.
See also: secretion