Definitions:
a mechanism for keeping a door, window, lid, or container fastened, typically operated by a key

a short section of a canal or river with gates and sluices at each end which can be opened or closed to change the water level, used for raising and lowering boats

the turning of the front wheels of a vehicle to change its direction of motion.

a player in the second row of a scrum.

a person or thing that is certain to succeed; a certainty

a mechanism for exploding the charge of a gun.

fasten or secure (something) with a lock

restrict access to the full functionality or data of (a computer, mobile phone, file, etc.), especially by requiring a user to verify their identity with a passcode or other form of authentication

make or become rigidly fixed or immovable

go through a lock on a canal

a piece of a person's hair that coils or hangs together