- a line, fired across a ship or boat, by means of which a hawser for a breeches buoy may be hauled aboard.
- a line or rope for saving life, as one attached to a lifeboat.
- any of various lines running above the decks, spars, etc., of a ship or boat to give sailors something to grasp when there is danger of falling or being washed away.
- a wire safety rope supported by stanchions along the edge of the deck of a yacht.
- the line by which a diver is lowered and raised.
- any of several anchored lines used by swimmers for support.
- a route or means of transportation or communication for receiving or delivering food, medicine, or assistance: This road is the town's lifeline and must be kept open despite the snow.
- assistance at a critical time.
- a line thrown or fired aboard a vessel for hauling in a hawser for a breeches buoy
- any rope or line attached to a vessel or trailed from it for the safety of passengers, crew, swimmers, etc
- a line by which a deep-sea diver is raised or lowered
- a vital line of access or communication
