The Collaborative International Dictionary
Snatch block
Snatch block \Snatch block\ (Naut.), a kind of block with an opening in one side to receive the bight of a rope.
Wiktionary
snatch block
n. 1 (context nautical English) A kind of block with an opening in one side to receive the bight of a rope. 2 (rfdef: English)
WordNet
snatch block
n. a pulley-block that can be opened to receive the bight of a rope
Usage examples of "snatch block".
When you lose a snatch block over the side in the middle of towing some silly bastard off a reef under air attack you just don't make the entry on the Title B card.
The rigging of the snatch block had increased the strength of the pull by several times and the schooner was inching up on the skids.