What does arithmetic mean?
The definition of arithmetic
A*rith”me*tic, n.
Etym: [OE. arsmetike, OF. arismetique, L. arithmetica, fr. Gr. 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.
2 A book containing the principles of this science. 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.