Rotation period refers to the time it takes for a planet to complete one full rotation on its axis. In other words, it measures the duration it takes for a planet to spin around once, resulting in the alternation of day and night.

The rotation period of a planet determines the length of its day, with one complete rotation corresponding to a full day-night cycle. For example, on Earth, the rotation period is approximately 24 hours, so we experience approximately 12 hours of daylight and 12 hours of darkness. However, it's important to note that the rotation period is not necessarily the same as the length of day or night everywhere on the planet. Factors such as the tilt of the planet's axis and its orbital path around the Sun can result in variations in the length of daylight throughout the year.

Different planets in our solar system have varying rotation periods. For instance, gas giant Jupiter has a relatively fast rotation period of about 10 hours, resulting in a shorter day and faster rotation speed compared to Earth. On the other hand, Venus has an extremely slow rotation period of about 243 Earth days, which means that a single day on Venus is longer than its entire year.