A clock was a stationary device used to keep track of the passage of time. It was commonly used on the planet Earth. The mobile version of a clock is called a watch.
By the 23rd century, clocks were used aboard starships in the form of onboard chronometers. (TOS: "Balance of Terror")
James T. Kirk kept an antique clock in his home during his first retirement from Starfleet. Sometime prior to 2293, he gave the clock to his friend, Leonard McCoy. (Star Trek: Generations)
While under the influence of the Saltah'na energy spheres, Benjamin Sisko built a complex mechanical clock. (DS9: "Dramatis Personae")
In an alternate timeline, Captain Kathryn Janeway was moved by her first officer Chakotay's defiance when she found the watch that he replicated against her direct order to salvage it. (VOY: "Year of Hell, Part II")