A license is an official permission that allows a person or organization to do something that they wouldn't normally be allowed to do. For example, a driver's license permits someone to operate a vehicle on public roads. Licenses are often issued by government authorities and come with specific rules and regulations that must be followed. In many professions, such as medicine or law, individuals need a professional license to practice legally. This ensures that they have the necessary training and qualifications. Without a proper professional license, someone could face legal consequences for practicing in that field.