arachnoidadj.n.
/əˈraknɔɪd/, U.S. /əˈrækˌnɔɪd/ A. adj.
1. Botany. Covered with or formed of long, delicate, cobweb-like hairs or fibres.
ΘΚΠ
the world > plants > part of plant > hair or bristle > [adjective] > having hair > cobweb-like
araneous1656
webbed1790
cobwebbed1828
arachnoid1857
1857 M. J. Berkeley Introd. Cryptogamic Bot. §401 An arachnoid or woven veil attached to the edge, and sometimes entirely covering the gills.
1874 M. C. Cooke Fungi 91 Arachnoid threads.
2. Physiology. Of or pertaining to the arachnoid. (See B.)
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the world > life > the body > nervous system > cerebrospinal axis > [adjective] > membranes > arachnoid
arachnoid1789
subarachnoid1819
subarachnoidal1828
arachnoidean1842
subarachnoidian1847
arachnoideous1851
arachnoidal1855
arachnoideal1877
1789 Loiterer 26 Sept. No. 35. p. 9 The dura and the pia Mater, and the arachnoid coat, entirely consisted of the Wings of Moths.
1836–9 Todd's Cycl. Anat. & Physiol. II. 278/1 The chamber is lined by the arachnoid membrane.
1872 T. H. Huxley Lessons Elem. Physiol. (ed. 6) xi. 249 It secretes..the arachnoid fluid.
3. Entomology. Resembling the Arachnida.
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the world > animals > invertebrates > phylum Arthropoda > class Arachnida > [adjective] > of nature of or resembling Arachnida
arachnoid1852
arachnidous1875
1852 J. D. Dana U.S. Exploring Exped.: Crustacea Pt. I 14 The Arachnoid type, as in Nymphon.
B. n.
The delicate serous membrane or membranous sac lining the dura mater, and enveloping the brain and spinal cord.
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the world > life > the body > nervous system > cerebrospinal axis > [noun] > membranes > arachnoid
arachnoid1839
1728 E. Chambers Cycl. Arachnoides..a fine, thin, transparent Membrane..supposed to invest the whole Substance of the Brain.]
1839–47 Todd's Cycl. Anat. & Physiol. III. 638/1 The arachnoid covers the superior surface of the cerebellum.
This entry has not yet been fully updated (first published 1885; most recently modified version published online June 2022).
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adj.n.1789