A citation is a reference or mention of a source in an academic or research paper. It provides the necessary information for readers to locate the original source and verify the information presented. Citations typically include the author's name, title of the work, publication date, and other relevant details depending on the citation style being used (e.g., MLA, APA, Chicago). Citations are important for academic integrity and to give credit to the original authors, strengthening the arguments and providing additional resources for curious readers.