Web Application

In software engineering, a Web application or webapp is an application that is accessed via web over a network such as the internet or an intranet.
An application in which all or some parts are downloaded from the Web each time it is run. The term typically refers to the use of Web browsers and Java applets. Web pages increasingly resemble the interactive behavior of local applications. Retrieving a Web page may cause the execution of code in the Web server as well as code in the HTML page brought into the user's machine. Clicking an icon on a Web page may cause a Java applet to be downloaded and executed in the user's machine.Client/Server ReduxA Web application may refer to any type of client/server interaction that uses the Web. A client program may reside in the user's machine that accesses data from a Web server rather than the local network server. See AJAX, thin client client/server,ASP and SaaS

Source: http://computing-dictionary.thefreedictionary.com