A web server is either a computer running program or a computer program, accepts HTTP request from clients, serving back HTTP responses with optional data contents, which can be represented usually are web pages as HTML documents and objects that are linked on it.
An application server is kind of software engine that deliver various applications to another device.
An application server is a server that provides software applications with services as security, transaction support, management of large distributed systems, transaction support and data services.
Web Server Vs Application Server
A web server Vs application server may differ on following points: