[arith.me.tic] n [ME arsmetrik, fr. OF arismetique, fr. L arithmetica, fr. Gk arithmetike, fr. fem. of arithmetikos arithmetical, fr. arithmein to count, fr. arithmos number; akin to OE rim number, and perh. to Gk arariskein to fit] (15c) 1 a: a branch of mathematics that deals usu. with the nonnegative real numbers including sometimes the transfinite cardinals and with the application of the operations of addition, subtraction, multiplication, and division to them b: a treatise on arithmetic
2: computation, calculation -- ar.ith.met.ic or ar.ith.met.i.cal adj -- ar.ith.met.i.cal.ly adv -- arith.me.ti.cian n