In JavaScript, a prototype is an object that serves as a template for creating new objects. When you create a new object, you can specify its prototype, which will be used to determine the properties and methods inherited by the new object. The prototype can also be used to add new properties and methods to an existing object. In addition, prototypes are used to implement inheritance, which is a way of creating new classes from existing classes. Inheritance allows you to reuse code and avoid errors caused by Duplicate code. Finally, prototypes can be used to create objects that have a specific type, such as an array or a function.