n. & adj.
n. 1 a the science of numbers. b one's knowledge of this (have improved my arithmetic). 2 the use of numbers; computation (a problem involving arithmetic).
adj. (also arithmetical) of or concerning arithmetic. arithmetic mean the central number in an arithmetic progression. arithmetic progression 1 an increase or decrease by a constant quantity (e.g. 1, 2, 3, 4, etc., 9, 7, 5, 3, etc.). 2 a sequence of numbers showing this. arithmetician n.
[ ME f. OF arismetique f. L arithmetica f. Gk arithmetike (tekhne) art of counting f. arithmos number ]