■ noun Brit. the hard, shiny dark brown nut of a horse chestnut tree.
↘( ~s ) [treated as sing. ] a children's game in which each has a ~ on a string and tries to break another's with it.
Origin
C19 (a dialect word denoting a snail shell, with which the game was orig. played): perh. from conch , but assoc. with conquer .