chi·tin /ˈkaɪtṇ/
  殼質,角素
  chi·tin /ˈkaɪtṇ/ 名詞
  Chi·tin n.  Chem. A white amorphous horny substance forming the harder part of the outer integument of insects, crustacea, and various other invertebrates; entomolin.
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  chitin
       n : a tough semitransparent horny substance; the principal
           component of the exoskeletons of arthropods and the cell
           walls of certain fungi