noun
or odd and even or odds or evens
: one of several games of chance or skill in which there is guessing or betting as to whether a certain number will be odd or even: as
a. : a game in which one player selects and holds an odd or even number of counters (as beans) and the other guesses which it is
b. : a game of betting on casts of dice or turns of a wheel
c. : a simplified form of fan-tan (sense 1)
d. : a mathematical game similar to nim in which the object is to take or leave an odd number of counters