thalamus

noun

thal·​a·​mus ˈtha-lə-məs How to pronounce thalamus (audio)
plural thalami ˈtha-lə-ˌmī How to pronounce thalamus (audio) -ˌmē How to pronounce thalamus (audio)
: the largest subdivision of the diencephalon that consists chiefly of an ovoid mass of nuclei in each lateral wall of the third ventricle and serves chiefly to relay impulses and especially sensory impulses to and from the cerebral cortex see brain illustration
thalamic
thə-ˈla-mik How to pronounce thalamus (audio)
adjective

Examples of thalamus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
These areas wake up the thalamus, which projects the instructions to the cortex. — Yasemin Saplakoglu, Quanta Magazine, 17 Oct. 2025 One of the main orchestrators of sleep is the thalamus, a deep-brain structure from which the isolated hemisphere is entirely cut off. — Allison Parshall, Scientific American, 20 Jan. 2026 In plain terms, most sensory information stops at the thalamus a kind of switchboard before being routed to other parts of the brain. — Lauren Jarvis-Gibson, Charlotte Observer, 16 June 2026 Sensory pain was thought to be mediated by the spinothalamic tract, a pathway that sends pain signals from the spinal cord to the thalamus, which then relays them to sensory processing areas across the brain. — Noah Lyons, San Diego Union-Tribune, 15 July 2025 See All Example Sentences for thalamus

Word History

Etymology

New Latin, from Greek thalamos chamber

First Known Use

1859, in the meaning defined above

Time Traveler
The first known use of thalamus was in 1859

Rhymes for thalamus

See All Rhymes for thalamus

Browse Nearby Words

Thalamophora
thalamus
Thalarctos
See all Nearby Words

Cite this Entry

“Thalamus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thalamus. Accessed 7 Jul. 2026.

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Kids Definition

thalamus

noun
thal·​a·​mus ˈthal-ə-məs How to pronounce thalamus (audio)
plural thalami -ˌmī How to pronounce thalamus (audio)
-ˌmē
: a subdivision of the forebrain that receives nerve impulses and sends them on to the appropriate parts of the brain cortex

Medical Definition

thalamus

noun
thal·​a·​mus ˈthal-ə-məs How to pronounce thalamus (audio)
plural thalami -ˌmī How to pronounce thalamus (audio) -ˌmē How to pronounce thalamus (audio)
: the largest subdivision of the diencephalon that consists chiefly of an ovoid mass of nuclei in each lateral wall of the third ventricle and serves to relay impulses and especially sensory impulses to and from the cerebral cortex

More from Merriam-Webster on thalamus

Nglish: Translation of thalamus for Spanish Speakers

Britannica.com: Encyclopedia article about thalamus

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