A web service can be defined as any web-based application that makes itself available over the internet and uses a standardized XML, SOAP, WSDL and UDDI as messaging system which can be downloaded.
XML: (computing) Extensible Markup Language; used for describing data in a structured text format for better understanding.
SOAP: Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of web services in computer networks.
WSDL: The Web Services Description Language is an XML-based interface definition language that is used for describing the functionality offered by a web service.
UDDI: Universal Description, Discovery and Integration is a platform-independent, Extensible Markup Language protocol includes a (XML)-based registry by which businesses worldwide can list themselves on the Internet, and a mechanism to register and locate web service applications.
