An annotation's an addition made to information in a book, document, online record, video, or other information.Commonly this's used, for example, in draft documents, where another reader has written notes about the quality of a document at a certain point, "in the margin", or perhaps just underlined or highlighted passages. Annotated bibliographies, give descriptions about how each source's useful to an author in constructing a paper or argument. Creating these comments, usually a few sentences… (More on Annotation)