The crossword solution for the term 'Listing in a Footnote' is 'SOURCE, ' which is a six-letter word. A SOURCE is a reference to a document, book, or other material that is used as evidence or support for an argument or claim. In the context of a footnote, a SOURCE is a reference to a document, book, or other material that is listed in the footnote as evidence or support for the argument or claim made in the main text.