Entities are like variables. They allow for one change to be reflected many times in a document. Entities are usually defined early in the document using the following syntax:
<!ENTITY ENTITYNAME "value">
Entities are then referred to in the document source with &ENTITYNAME;. The most common use of entities are for phrases like the current version of a product or the product name.
Entities do not appear in the PO files for a document, and are therefore untranslateable. Only use an entity for wording that does not require translation ("Fedora", for example)
