Supplementary material refers to additional content that supports or enhances the main text of a document, such as a research paper or book. This can include tables, figures, charts, or appendices that provide extra data or explanations, helping readers better understand the primary information presented. In academic publishing, supplementary material is often made available online, allowing readers to access it easily without cluttering the main document. This material can also include multimedia elements like videos or audio recordings, which further enrich the reader's experience and comprehension of the subject matter, such as scientific studies or educational resources.