Exocrine: Pertaining to the secretion of a substance out through a duct. The exocrine glands include the salivary glands, sweat glands and glands within the gastrointestinal tract. Exocrine is as opposed to endocrine which refers to the secretion of a substance (a hormone) into the bloodstream. The exocrine glands are the "glands of external secretion" while the endocrine glands are "glands of internal secretion."
