Dictionary.net

any of the glands of the endocrine system that secrete hormones directly into the bloodstream

of or belonging to endocrine glands or their secretions; "endocrine system"

the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect

any of the glands of the endocrine system that secrete hormones directly into the bloodstream

of or belonging to endocrine glands or their secretions; "endocrine system"

1. The internal secretion of a gland. 2. Noting a gland which furnishes an internal secretion.