arachnoid

adjective (1)
arach·​noid | \ ə-ˈrak-ˌnȯid How to pronounce arachnoid (audio) \

Definition of arachnoid

 (Entry 1 of 3)

1 : of or relating to a thin membrane of the brain and spinal cord that lies between the dura mater and the pia mater
2 : covered with or composed of soft loose hairs or fibers

arachnoid

noun

Definition of arachnoid (Entry 2 of 3)

: an arachnoid membrane

arachnoid

adjective (2)

Definition of arachnoid (Entry 3 of 3)

: resembling or related to the arachnids

First Known Use of arachnoid

Adjective (1)

1789, in the meaning defined at sense 1

Noun

1804, in the meaning defined above

Adjective (2)

1825, in the meaning defined above

History and Etymology for arachnoid

Noun

New Latin arachnoides, from Greek arachnoeidēs, like a cobweb, from arachnē spiderweb

Adjective (2)

New Latin Arachnida + English -oid

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Time Traveler for arachnoid

Time Traveler

The first known use of arachnoid was in 1789

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Cite this Entry

“Arachnoid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/arachnoid. Accessed 26 Jul. 2021.

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More Definitions for arachnoid

arachnoid

noun
arach·​noid | \ ə-ˈrak-ˌnȯid How to pronounce arachnoid (audio) \

Medical Definition of arachnoid

 (Entry 1 of 2)

: a thin membrane of the brain and spinal cord that lies between the dura mater and the pia mater

arachnoid

adjective
variants: also arachnoidal \ ə-​ˌrak-​ˈnȯid-​ᵊl How to pronounce arachnoid (audio) \

Medical Definition of arachnoid (Entry 2 of 2)

: of or relating to the arachnoid the arachnoid membrane

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