In TypeScript, an interface is a syntactical contract that defines how a class or object should look and behave. In other words, it is a blueprint for objects.

Interfaces define properties, methods, and events, which are the members of the interface. A class or object can implement one or more interfaces to inherit the members of the interface.

A class can implement an interface by using the implements keyword. For example:

    class Car implements ICar { 
        //class definition goes here 
    } 

An interface can extend one or more other interfaces. This is done by using the extends keyword. For example:

    interface ICar { 
        //interface definition goes here 
    } 

    interface IConvertible extends ICar { 
        //interface definition goes here 
    } 

In the above example, the IConvertible interface inherits all the members of the ICar interface.