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snatch block

American  

noun

Nautical.
  1. a fairlead having the form of a block that can be opened to receive the bight of a rope at any point along its length.


snatch block British  

noun

  1. nautical a block that can be opened so that a rope can be inserted from the side, without threading it through from the end

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of snatch block

First recorded in 1615–25