Entities are Processed Recursively

This means that the replacement text of an entity (except when in an attribute value or entity declaration, see below) is processed as if it were part of the document; in particular, this means that it can contain other entity references, which are processed recursively. This means that in the following:

<!ENTITY AC "The &W3C; Advisory Council">
<!ENTITY W3C "WWW Consortium">

The reference &AC; would result in the string The WWW Consortium Advisory Council appearing as character data in the document.

Back-link to spec

Copyright © 1998, Tim Bray. All rights reserved.