(biology) Any of several mechanisms that regulate the periodicity of biological functions. / The progression from puberty to menopause during which a woman can bear children.

A clock built into a case.

A freestanding weight-driven pendulum clock, having the pendulum and weights in a tall case.

A small clock with a carrying handle, originally designed for travelling.

(transitive, figuratively) To accumulate (an amount of time or experience). / (transitive, figuratively, Britain) To cover (a distance) over time.

(relativity) The phenomenon in which two observers who start together with identical clocks, follow different timelines, and then rejoin can have different elapsed times on their clocks, especially if one travels at a relativistic speed.

A device consisting of two clocks and a switch for running one at a time, used in chess and other games to measure how much time each player takes.

A clock mounted on a wall.

A clock that announces the time (hours and quarter hours) by a cuckoo sound, often equipped with a small cuckoo automaton.

plural of cuckoo clock