The Collaborative International Dictionary of English v.0.48:

Chop \Chop\, n. [Chin. & Hind. ch[=a]p stamp, brand.]
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   1. Quality; brand; as, silk of the first chop.
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   2. A permit or clearance.
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   Chop dollar, a silver dollar stamped to attest its purity.


   chop of tea, a number of boxes of the same make and quality
      of leaf.

   Chowchow chop. See under Chowchow.

   Grand chop, a ship's port clearance. --S. W. Williams.
      [1913 Webster]