di·​en·​ceph·​a·​lon ˌdī-ən-ˈse-fə-ˌlän How to pronounce diencephalon (audio)
-lən How to pronounce diencephalon (audio)
: the posterior subdivision of the forebrain
ˌdī-ən-sə-ˈfa-lik How to pronounce diencephalon (audio)

Examples of diencephalon in a Sentence

Recent Examples on the Web Though people in vegetative states are cognitively non-responsive, the brain stem and the brain region called the diencephalon are usually preserved. Adrian Owen, Discover Magazine, 12 Nov. 2017 The diencephalon regulates sleep-wake cycles and motor reflexes, while the brain stem controls automatic functions like breathing, blood pressure, heart rate, swallowing and pupil dilation. Adrian Owen, Discover Magazine, 12 Nov. 2017 This gene is involved in brain development and is mostly expressed in a part of the brain called the diencephalon — an area previously found to differ in gay men. Leah Froats, Discover Magazine, 7 Dec. 2017

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'diencephalon.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin, from dia- + encephalon

First Known Use

circa 1883, in the meaning defined above

Time Traveler
The first known use of diencephalon was circa 1883

Dictionary Entries Near diencephalon

Cite this Entry

“Diencephalon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diencephalon. Accessed 19 May. 2024.

Medical Definition


di·​en·​ceph·​a·​lon ˌdī-ən-ˈsef-ə-ˌlän How to pronounce diencephalon (audio) ˌdī-(ˌ)en- How to pronounce diencephalon (audio)
: the posterior subdivision of the forebrain

called also betweenbrain, interbrain

diencephalic adjective
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