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a·rach·noid

(ə-răknoid′)

adj.

1. Anatomy Of or relating to a delicate membrane enclosing the spinal cord and brain.

2. Of, relating to, or resembling arachnids.

3. Covered with or consisting of thin, soft, entangled hairs or fibers resembling those of a cobweb or spider's web.

1. An arachnid.

2. Anatomy A delicate membrane that encloses the spinal cord and brain and lies between the pia mater and dura mater.

[New Latin arachnoīdēs, from Greek arakhnoeidēs, cobweblike : arakhnē, spider + -oeidēs, -oid.]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

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Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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