four-color problem

[ fawr-kuhl-er, fohr- ]

/ ˈfɔrˈkʌl ər, ˈfoʊr- /

noun Mathematics.

the problem, solved in 1976, of proving the theorem that any geographic map can be colored using only four colors so that no connected countries with a common boundary are colored the same color.

Words nearby four-color problem

four-banger, four-by-four, four-by-two, four-channel, four-color, four-color problem, four-colour, four-corners, four-cycle, four-deal bridge, four-dimensional

Origin of four-color problem

First recorded in 1875–80

Also called four-color theorem.