A living document, also known as an evergreen document or dynamic document, is a document that is continually edited and updated. An example of a living document is an article in Wikipedia, an online encyclopaedia that permits anyone to freely edit its articles; this is in contrast to “dead” or “static” documents, such as an article in a single edition of the Encyclopædia Britannica.
A living document may or may not have a framework for updates, changes, or adjustments.
However, a living document may evolve through successive updates, be expanded as needed, and serve a different purpose over time. Living documents are changed through revisions that may or may not reference previous iterative changes.
Sourced from: https://en.wikipedia.org/wiki/Living_document