Disco
The Web Service Discovery Tool (DISCO) is used to discover the URLs of XML Web Services located on a Web server and saves documents related to each XML service on a local disk. The DISCO takes the URL and discovers and produce publishes discovery documents (.wsdl, .xsd, .disco and .dicomap files) as arguments.
UDDI
Universal Description, Discovery and Integration (UDDI) is a platform independent framework functioning like a directory that provides a mechanism to locate and register web services on the internet.
WSDL
Web Services Description Language (WSDL) is a markup language that describes the web service.