Active users refer to individuals who regularly engage with a particular platform, service, or application within a specified time frame. This metric is commonly used in the tech industry to measure user engagement and the overall health of a product. For example, a social media platform may define active users as those who log in at least once a month. The concept of active users can be broken down into different categories, such as daily active users (DAU) and monthly active users (MAU). These metrics help businesses like Facebook or Twitter understand user behavior and make informed decisions about features, marketing strategies, and overall growth.