lock

Something used for fastening, which can only be opened with a key or combination.

(by extension) A mutex or other token restricting access to a resource.

A segment of a canal or other waterway enclosed by gates, used for raising and lowering boats between levels.

The firing mechanism.

Complete control over a situation.

Something sure to be a success.

A player in the scrum behind the front row, usually the tallest members of the team.

A fastening together or interlacing; a closing of one thing upon another; a state of being fixed or immovable.

A place from which egress is prevented, as by a lock.

A device for keeping a wheel from turning.

A grapple in wrestling.