A mechanism for keeping a door, lid, etc., fastened, typically operated only by a key of a particular form. A short confined section of a canal or other waterway in which the water level can be changed by the use of gates and sluices, used for raising and lowering vessels between two gates. A person or thing that is certain to succeed; a certainty. A mechanism for exploding the charge of a gun. A piece of a person's hair that coils or hangs together. Fasten or secure (something) with a lock. Make or become rigidly fixed or immovable. Go through a lock on a canal.