sprock·et /ˈsprɑkət/
  鏈輪齒
  sprocket
  輸送孔
  sprocket
  鏈齒
  Sprock·et n.  Mach. (a) A tooth or projection, as on the periphery of a wheel, shaped so as to engage with a chain. (b) A sprocket wheel.
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  sprocket
       n 1: roller that has teeth on the rims to pull film or paper
            through
       2: thin wheel with teeth that engage with a chain [syn: sprocket
          wheel]
       3: tooth on the rim of gear wheel [syn: cog]