Web Server is program that uses hyper text transfer protocol also known as HTTP. It is used to serve the files of website in form of web pages to the users, in response to the requests made on client side. The term can also be referred to entire system or software that accepts and supervises the http requests.
Leading Web servers include Apache (the most widely-installed Web server), Microsoft's Internet Information Server (IIS) and nginx (pronounced engine X) from NGNIX. Other Web servers include Novell's NetWare server, Google Web Server (GWS) and IBM's family of Domino servers