|Content re-use / Variables|
Internal entities are an XML feature for creating typing shortcuts. They should be avoided in DITA authoring.
Internal entities function as typing shortcuts in XML documents. They allow a string or phrase to be defined in the head of the XML file, and then used in the body of the content using a shortcut notation. For example, the phrase "Supara Lumberer" may be defined as <!ENTITY lumberer "Supara Lumberer">, and that lumberer entity used within the document as &lumberer;. They can theoretically be used for creating variables.
Do not use internal entities. Their use inhibits interchange, and they are technically difficult for authors to work with. They are also changed during XSL transformations, resulting in inconsistent output results.