On a page, “above” can mean “higher up” — the lines you already passed. Above-mentioned is a stiff, paper word for “the person, place, or thing I already named higher on this page, or on a page before this.” Contracts, school notices, and official letters love it: “the above-mentioned student,” “the above-mentioned rules.” You almost never hear it in speech. A person talking would say “the one I just named” or “that company I told you about.” Even in writing, many people now just say “above” (“see above”). Use above-mentioned when the document is formal and you must point back clearly; skip it in a message to a friend, where it sounds as if you swallowed a government form.