A tough, protective, semitransparent substance, primarily a nitrogen-containing polysaccharide, forming the principal component of arthropod exoskeletons and the cell walls of certain fungi.

• 几丁质一种基本上为含氮多聚糖的保护性半透明坚硬物质，是节肢动物外骨骼和某些真菌类植物细胞壁的主要组成部分