A lanyard in sailing is a short line, cord, or wire used to fasten, secure, or tauten4 objects on a vessel. Historically, they were essential for tensioning standing rigging (deadeyes), but modern usage often refers to small lines used to secure equipment like knives, buckets, or deck plates.

Key Descriptions and Functions
Securing Equipment: A short line used to fasten portable items (e.g., a knife, bosun's pipe, or deck plate lid) to the ship to prevent them from falling overboard.

Rigging Adjustment: Historically and in traditional rigging, a line rove through deadeyes to tighten standing rigging.

Safety Kill Switch: A crucial modern safety device. It is a cord connected at one end to the skipper and the other to the engine's ignition, designed to cut the motor immediately if the operator falls overboard.

Firing Cannon: A cord with a hook used in traditional naval contexts to fire cannons.

Origin: The term originates from the 14th-century French word laniere, meaning a thong or strap, and has been used in a nautical context to refer to small lines used on ships for hundreds of years.