Hormone
"Endocrine" means secreting directly into the blood. Most internal secretions are from endocrine glands. The opposite word is "exocrine", which means secreting through a duct or tube. Some hormones are produced by exocrine glands, and some exocrine secretions release outside the body. Sweat glands and salivary glands are examples of exocrine glands whose products are released outside the body.