Explanatory matter refers to additional information about a topic or subject that helps to clarify and understand its meaning or purpose. Synonyms for explanatory matter include supporting details, elucidation, exposition, clarification, extras, annotation, commentary, context, background, and footnotes. These synonyms provide readers or listeners with a deeper understanding of the subject by offering further explanation or examples that support the main message conveyed. Using synonyms for explanatory matter can improve the clarity and readability of written or spoken communication by indicating that additional details are available for those who require them.