The Collaborative International Dictionary of English v.0.48:

Arithmetic \A*rith"me*tic\, n. [OE. arsmetike, OF. arismetique,
   L. arithmetica, fr. Gr. ? (sc. ?), fr. ? arithmetical, fr. ?
   to number, fr. ? number, prob. fr. same root as E. arm, the
   idea of counting coming from that of fitting, attaching. See
   Arm. The modern Eng. and French forms are accommodated to
   the Greek.]
   1. The science of numbers; the art of computation by figures.
      [1913 Webster]

   2. A book containing the principles of this science.
      [1913 Webster]

   Arithmetic of sines, trigonometry.

   Political arithmetic, the application of the science of
      numbers to problems in civil government, political
      economy, and social science.

   Universal arithmetic, the name given by Sir Isaac Newton to
      algebra.
      [1913 Webster]