Acronym for Simple Object Access Protocol.

A way for a computer program to call a function on a website. The usual SOAP example is quering a web server at IBM which returns (delayed) stock quotes.

This Wiki has a SOAP source letting you grab the wiki source of a webpage.

The WSDL file describing this source is http://www.wlug.org.nz/phpwiki/soap.wsdl, a webbrowser friendly URL is http://www.xmethods.net/ve2/WSDLAnalyzer.po;?wsdlurl=http%3A%2F%2Fwww.wlug.org.nz%2Fphpwiki%2Fsoap.wsdl

SOAP is often viewed as a bloated, over engineered implementation of a perfectly trivial concept, but it's the first generic, cross platform, language independent implementation of that concept to achieve widespread adoption, so maybe it needed to be.

See also AXIS.