Super official-sounding definition:
An annotated bibliography is a comprehensive list of sources (such as books, articles, and documents) on a particular topic, accompanied by a brief descriptive and evaluative summary of each source. Each annotation typically includes a concise summary of the source's content, its relevance to the research topic, the author's credentials, the methodology used, and an assessment of its quality and usefulness for the research project. An annotated bibliography provides readers with a deeper understanding of the sources cited, helping researchers evaluate the credibility and relevance of each reference in relation to their research objectives.
asked and copied from Perplexity.ai