pineal body pi·neal·body uncommon noun 1. a small endocrine gland in the brain; situated beneath the back part of the corpus callosum; secretes melatonin Synonymspineal glandpineal bodyepiphysis cerebriepiphysis Related words Broader terms endocrine gland WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
