12 PM, also known as noon, is the time of day when the sun is at its highest point in the sky. It marks the transition from morning to afternoon. In a 12-hour clock system, 12 PM is the point where the clock resets from AM to PM. In many cultures, 12 PM is associated with lunchtime, as people often take a break to eat around this time. It is also significant in various fields, such as astronomy, where it helps in determining solar noon, and in business, where it can signify deadlines or meeting times.