XSL

In computing, the term Extensible Stylesheet Language (XSL) is used ambiguously to refer to the languages XSLT and XSL-FO which are used to transform and render XML documents (e.g., XSLT is used to determine how to display a XML document as a webpage).

1. XSL Transformation (XSLT): an XML language for transforming XML documents
2. XSL Formatting Objects (XSL-FO): an XML language for specifying the visual formatting of an XML document. It's an intermediary format which can be used when transforming from XML with XSLT to a print format like PDF. Using XSL-FO usually implies using XSLT too.