dec·i·mal / ˈdes(ə)məl/ • adj. relating to or denoting a system of numbers and arithmetic based on the number ten, tenth parts, and powers of ten: decimal arithmetic. ∎  relating to or denoting a system of currency, weights and measures, or other units in which the smaller units are related to the principal units as powers of ten: decimal coinage.• n. (also decimal fraction) a fraction whose denominator is a power of ten and whose numerator is expressed by figures placed to the right of a decimal point. ∎  the system of decimal numerical notation.DERIVATIVES: dec·i·mal·ly adv.

decimal proceeding by powers of 10; also sb. XVII. — modL. decimālis, f. decimus tenth, f. decem TEN; see -AL 1.