¹ clock noun

• a device that shows what time it is and that is usually placed in a room or attached to a wall —often used before another noun
• a clock that is used in sports and that shows how much time remains for a particular part of a game
• time clock

² clock verb

• to measure the amount of time it takes for (a person) to do something or for (something) to be completed—usually + at
• to finish a race in (an amount of time)
• to measure or show (the speed of something) with a measuring device