'Snatch block' definitions:

Definition of 'snatch block'

(from WordNet)
noun
A pulley-block that can be opened to receive the bight of a rope

Definition of 'Snatch block'

From: GCIDE
  • Snatch block \Snatch block\ (Naut.), a kind of block with an opening in one side to receive the bight of a rope. [1913 Webster]