- -ics1. There are a few names of arts or of branches of study that end in -ic, of which the most important in general use are logic, magic, music, and rhetoric. Otherwise the normal ending for terms of this kind is -ics: acoustics, classics, economics, ethics, mathematics, obstetrics, physics, and many others. (In some cases a singular noun exists with a different meaning: a classic is something of acknowledged fame or quality, an ethic is a set of moral principles, and a statistic is an item of statistical data.) Although these are plural forms, they take singular verbs when they are the name of a subject and a plural verb when they are used generally: compare Economics is her main interest and The economics of the foreign aid are extremely complex.2. Another class of nouns in -ics corresponds to adjectives in -ic or -ical, e.g. heroics, hysterics, tactics, and these are treated as regular plurals, e.g. Heroics are out of place.
Modern English usage. 2014.