In general, it is a web application framework, helps us in creating web applications using HTML, CSS and JavaScript. It is a opensource framework by Google.
AngularJS is a JavaScript MVC framework developed by Google that lets you build well structured, easily testable, and maintainable front-end applications. iF you want more detail then you may this url http://www.toptal.com/angular-js/a-step-by-step-guide-to-your-first-angularjs-app
AngularJs is Framework its has own Model,View and controller. Basically AngularJs Is used for the making of single page web application. The main benefit of AngularJs is Its two way data binding which allow you complete separation of Data model and View
AngularJS is an open-source JavaScript framework developed by Google. It helps you to create single-page applications or one-page web applications that only require HTML, CSS, and JavaScript on the client side. It is based on MV-* pattern and allow you to build well structured, easily testable, and maintainable front-end applications. AngularJS has changed the way to web development. It is not based on jQuery to perform its operations. In spite of using ASP.NET Web form, ASP.NET MVC, PHP, JSP, Ruby on Rails for web development.
http://www.w3schools.com/angular/
AngularJS is a JavaScript framework that helps build applications that run in a web browser. Google is the company that developed AngularJS. AngularJS is an open-source project, which means it can be freely used, changed, and shared by anyone.AngularJS is an excellent framework for building both Single Page Applications (SPA) and Line of Business Applications. Many companies are using Angular today, and there are many public facing websites that are built with angular.
http://www.c-sharpcorner.com/UploadFile/f2823e/introduction-to-angularjs/
thanks @Sooraj Singh