1. a tackle consisting of a single rope rove through a single movable block, used for hoisting
Usage: nautical

Examples

• The sailors used a lewisson to hoist the heavy cargo aboard.
• The lewisson made it easier to lift the anchor chain.
• He rigged a simple lewisson to raise the sail.
• The crew attached the lewisson to the boom for better leverage.
• A lewisson is essential equipment on most sailing vessels.