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pineal gland

noun
  1. a small, cone-shaped endocrine organ in the posterior forebrain, secreting melatonin and involved in biorhythms and gonadal development.
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Origin of pineal gland

First recorded in 1705–15
Also called epiphysis.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for pineal gland

pineal gland

pineal body

noun
  1. a pea-sized organ in the brain, situated beneath the posterior part of the corpus callosum, that secretes melatonin into the bloodstreamTechnical names: epiphysis, epiphysis cerebri
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

pineal gland in Medicine

pineal gland

n.
  1. pineal body
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

pineal gland in Science

pineal gland

  1. A small gland located near the brain and primarily involved in the production and secretion of the hormone melatonin, which regulates circadian rhythms in many animals, including humans.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.