A transformation is specified by a "stylesheet" or "transform" document:

<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
   version='1.0'
>
  <!-- your rules here -->
</xsl:transform>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
   version='1.0'
>
  <!-- your rules here -->
</xsl:stylesheet>

The document element name has no effect on the outcome.

Applications may interpret 'stylesheet' differently from 'transform' in terms of:

• whether they run the transformation

• what they do with the results.