AnjularJS is a structured MVC based framework best suited for creating Single Page Web Application development. It extents HTML, CSS, JQuery trio and allows data binding and dependency injection to make it the best choice for client-side technology.
AngularJS by Google is an open-source framework maintained by Google and community. While building user interface for single page applications declarative programming approach is believed to be the best and AngularJS follows that. AngularJS extends HTML from its static state and make is more expressive. It achieves this by a new approach called directives which minimize the impedance mismatch between static HTML and dynamic application requirements.
The features like two-way data binding, template manipulation, dependency injection, directives etc differentiates AngularJS from other traditional java script libraries like JQuery.