The term WRITE A FOOTNOTE can be summarized as the act of citing a source in a document. A footnote is a reference, comment, or explanation that is added to the bottom of a page in a document. Footnotes are typically used to provide additional information on a topic or to CITE sources. CITE, the four letter solution to the crossword, is an abbreviation for the verb 'to CITE, ' which means to quote or refer to a source.