In sailing, a line is the general term for any rope used on a vessel once it has a specific, functional purpose (such as controlling sails, securing the boat, or supporting the mast). Unlike generic ropes, lines are working, specialized, and often under tension.

Key types of lines include:
Halyards: Lines specifically used to raise or lower sails.

Sheets: Lines that control the trim (angle) of the sails.

Docklines/Warps: Lines used for mooring or docking the boat.

Shrouds/Stays: Standing rigging (often wire) that supports the mast.

Fun Fact: It is often said there is only one "rope" on a boat: the bell rope used to ring the ship’s bell. All others are lines, sheets, or halyards.