arachnoid arachnitis • arachnoidal · · · Info · Definitions · Synonyms · Characters · · arachnoid · · Text Latin · · Script 9 · · Length Definitions · · · (noun) the middle of the 3 meninges. Synonyms: arachnoid membrane. · · Noun Definition 1 (noun) air-breathing arthropods characterized by simple eyes and four pairs of legs. Synonyms: arachnid. · · Noun Definition 2 (adj) relating to or resembling a member of the class Arachnida. Synonyms: arachnidian, spidery, spiderlike, spiderly. · · Adjective Definition 1 Synonyms · · · arachnoid membrane · · Synonym 1 arachnid · · Synonym 2 arachnidian · · Synonym 3 spidery · · Synonym 4 spiderlike · · Synonym 5 spiderly · · Synonym 6 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 h latin small letter h U+0068 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072