A timekeeper is someone or something that measures, tracks, or records time. In sports, the timekeeper is the official who starts and stops the clock, making sure the game follows the proper timing rules. At a track meet, timekeepers record how long it takes each runner to finish their race, often using stopwatches to capture times down to hundredths of a second.

The word also refers to how reliably something keeps time. A watch that runs accurately is a “good timekeeper,” while one that constantly runs fast or slow is a “poor timekeeper.” Before people had digital clocks and smartphones, craftspeople built elaborate mechanical timekeepers: pocket watches with tiny gears and springs, grandfather clocks with swinging pendulums, and eventually wristwatches that people could wear anywhere.

In workplaces, a timekeeper might be someone who tracks employees' hours, recording when they arrive and leave. Historically, factory timekeepers kept attendance records and calculated wages based on hours worked.

The idea of timekeeping has shaped human civilization. Ancient peoples built sundials and water clocks to track time. In the 1700s, incredibly precise marine timekeepers called chronometers helped sailors navigate across oceans by calculating their longitude. Today's atomic clocks are so accurate they won't lose even a second for millions of years.