Frequency refers to the number of times an event occurs within a specific time period. In physics, it is often used to describe waves, such as sound or light, indicating how many cycles happen in one second. The unit of frequency is the hertz (Hz), where one hertz equals one cycle per second. In everyday life, frequency can apply to various situations, such as how often a person exercises or how frequently a train arrives at a station. Understanding frequency helps in analyzing patterns and making predictions in fields like music, communication, and health.