Leonardo da Vinci designed a miter lock for canals to help boats pass between different water levels.
A miter lock has two gates that meet at an angle pointing upstream. Water pressure pushes the gates together, helping them seal the chamber. By filling or emptying the lock chamber, boats can be raised or lowered between canal sections.
Leonardo studied canal engineering in northern Italy and developed improved lock arrangements, including paired gates that could control water more effectively. His work was connected with the waterways around Milan, where canals supported transport, irrigation, and construction.
Leonardo did not invent the entire principle of canal locks, which existed before his studies. His importance lies in refining mechanisms and recording practical engineering solutions. A miter lock is therefore more specific than the broader term canal lock.