odd or even

or odds or evens

noun

any of various games of chance in which one bets on an odd or even number, as one in which two players alternately draw from a pile of an odd number of counters any desired number up to a prearranged limit, the object being to have drawn an odd number of counters at the end of the game.

Also odd and even.

Origin of odd or even

First recorded in 1625–35