[ fawr-breyn, fohr- ]
/ ˈfɔrˌbreɪn, ˈfoʊr- /
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noun Anatomy.
Also called prosencephalon. the anterior of the three primary divisions of the brain in the embryo of a vertebrate, or the part of the adult brain derived from this tissue including the diencephalon and telencephalon.
the telencephalon.
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Origin of forebrain

First recorded in 1875–80; fore- + brain
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use forebrain in a sentence

  • The “random activation theory” suggests that dreams are our forebrains trying to make sense of the random activity sent to it by the chaotic and meaningless information coming from the back of the brain during sleep.

  • The molecules mingle with the molecules of serum: In seconds they are washed against the cell-walls of the forebrain.

    The Syndic|C.M. Kornbluth
  • He jerked his mind away suddenly from the thoughts which had crowded into his forebrain.

    Cum Grano Salis|Gordon Randall Garrett
  • Autopsies on imbeciles show an infantile development of the forebrain.

British Dictionary definitions for forebrain

/ (ˈfɔːˌbreɪn) /

the nontechnical name for prosencephalon
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

Medical definitions for forebrain

[ fôrbrān′ ]

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

Scientific definitions for forebrain

[ fôrbrān′ ]

The forwardmost part of the vertebrate brain. In humans, it consists of the thalamus, the hypothalamus, and the cerebrum. Compare hindbrain midbrain.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.