[1] : The Collaborative International Dictionary of English v.0.48

arachnida \arach"nida\, n. pl. nl., fr. gr. ? spider.
   zool.
   one of the classes of arthropoda. see illustration in
   appendix.
   1913 webster

   note: they have four pairs of legs, no antennae nor wings,
         a pair of mandibles, and one pair of maxillae or
         palpi. the head is usually consolidated with the
         thorax. the respiration is either by trancheae or by
         pulmonary sacs, or by both. the class includes three
         principal orders: araneina, or spiders;
         arthrogastra, including scorpions, etc.; and
         acarina, or mites and ticks.
         1913 webster
see also:
araneina arthrogastra acarina 

[2] : The Collaborative International Dictionary of English v.0.48

araneina \ara`nei"na\ .ar=a`n-eimac"n.a, n. pl.
   nl., fr. l. aranea spider. zool.
   the order of arachnida that includes the spiders.
   1913 webster

   note: they have mandibles, modified as poison fangs, leglike
         palpi, simple eyes, abdomen without segments, and
         spinnerets for spinning a web. they breathe by
         pulmonary sacs and tracheae in the abdomen. see
         illustration in appendix.
         1913 webster

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Araneina, definition of term: Araneina
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