A clepsydra, also known as a water clock, is an ancient timekeeping device that measures time through the flow of water. It typically consists of a container that allows water to drip at a constant rate, with markings to indicate the passage of time. Clepsydras were used in various cultures, including ancient Egypt and Greece, to time events such as speeches and rituals. These devices were significant before the invention of mechanical clocks, providing a reliable way to measure time. The design of clepsydras varied, with some featuring intricate decorations and others being quite simple. They highlight the ingenuity of early civilizations in their quest to understand and measure time.