It isn't "short for" anything. This is just a normal suffix for fields of study: Physics, mechanics, politics, statistics, optics, ethics, linguistics, and so on.
Etymologically it is a plural suffix, but in modern English it is singular.
Etymologically it is a plural suffix, but in modern English it is singular.
Was mathematics once referred to as "the mathematical arts" or something?
(A similar way to appear very uncool is to walk into a record shop and proclaim, "look at all these vinyls!")