jack rope

noun Nautical.
  1. a rope for bending the foot of a sail to a boom.
  2. a line that is rove through grommets on the reef band of a square sail, and to which lanyards from the jackstay on the yard are toggled to reef the sail.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018