forebrain

noun

fore·​brain ˈfȯr-ˌbrān 

: the anterior of the three primary divisions of the developing vertebrate brain or the corresponding part of the adult brain that includes especially the cerebral hemispheres, the thalamus, and the hypothalamus and that especially in higher vertebrates is the main control center for sensory and associative information processing, visceral functions, and voluntary motor functions

called also prosencephalon

compare diencephalon, telencephalon

Examples of forebrain in a Sentence

Recent Examples on the Web

Differences between the mid- and forebrain seem to arise later, and largely due to the action of signaling molecules that diffuse through the developing brain and provide positional information. — John Timmer, ArsTechnica, 23 Sep. 2026

One big question has always been whether cells in the ectoderm were already destined to become the forebrain, midbrain, and hindbrain. — Mike McRae 21, New Atlas, 22 Sep. 2026

That means damage to parts of the forebrain, although serious, won’t necessarily incapacitate the entire animal. — Scott Travers, Forbes.com, 16 May 2026

Throughout the day, adenosine gradually accumulates as a byproduct of brain activity, increasing feelings of sleepiness by inhibiting wake-promoting regions such as the basal forebrain. — Samantha Agate, Sacbee.com, 5 May 2026

Word History

First Known Use

1879, in the meaning defined above

Rhymes for forebrain

• aeroplane
• appertain
• ascertain
• capitaine
• cassegrain
• cellophane
• chatelaine
• counterpane
• entertain
• halothane
• hurricane
• hyperplane

Kids Definition

forebrain

noun

fore·​brain ˈfō(ə)r-brān 

ˈfȯ(ə)r-

: the front division of the embryonic brain of a vertebrate animal or the parts developed from it

Medical Definition

forebrain

noun

fore·​brain -ˌbrān 

: the anterior of the three primary divisions of the developing vertebrate brain or the corresponding part of the adult brain that includes especially the cerebral hemispheres, the thalamus, and the hypothalamus and that especially in higher vertebrates is the main control center for sensory and associative information processing, visceral functions, and voluntary motor functions

called also prosencephalon

see diencephalon, telencephalon