Definition of: life line

1. A rope shot to a wrecked ship by which a heavier line for a breeches buoy may be rigged.
2. A line attached to a buoy, mast, etc., which may be clung to, as by bathers, sailors in stormy weather, etc.
3. A line for raising and lowering a diver.
4. Any route for transporting vital supplies.
5. In palmistry, a line about the base of the thumb which allegedly foretells facts of a person's life.