AngularJS is a JavaScript framework for building dynamic and interactive web applications. It provides a structured approach to web development with features like data binding, dependency injection, and reusable components. AngularJS is known for its two-way data binding, allowing seamless synchronization between the user interface and data model. It supports modular development, making it easy to organize code and maintain large applications. Although newer versions (Angular 2+) offer significant improvements, AngularJS remains popular in legacy projects.