flat (subs.) Copy link Outline I. A level surfaceII. A storeyIII. Colloq. a foolish personIV. In music, a note depressed by a semitone • flat (subs.): I. A level surface: plānĭties, ēi: v. plain. II. A storey: tăbŭlātum: v. storey. III. Colloq. a foolish person: homo ineptus, insulsus, stultus: v. fool. IV. In music, a note depressed by a semitone: (vocula) mollis (?): cf. Germ. moll.