An old game played with counters, or men, which are placed at the angles of a figure drawn on a board or on the ground; also, the board or ground on which the game is played. [1913 Webster
" The figure consists of three concentric squares, with lines from the angles of the outer one to those of the inner, and from the middle of each side of the outer square to that of the inner. The game is played by two persons with nine or twelve pieces each (hence called nine-men's morris or twelve-men's morris). The pieces are placed alternately, and each player endeavors to prevent his opponent from making a straight row of three. Should either succeed in making a row, he may take up one of his opponent's pieces, and he who takes off all of his opponent's pieces wins the game."
"The nine-men's morris is filled up with mud."