Sudoku

noun
1.
a puzzle printed on a square grid of nine large squares each subdivided into nine smaller squares, the object of which is to fill in each of the 81 squares so that each column, row, and large square contains every number from 1 to 9.
noun
1.
a type of puzzle in which numbers must be arranɡed within a ɡrid contaninɡ several internal squares so that no number is repeated in the same row, column, or internal square
noun

a puzzle consisting of a 3-by-3 grid of nine squares, each of which is similarly divided into nine smaller squares, some containing a number. The aim is to fill in numerals from 1 to 9 so that every horizontal and vertical line and every large 3-by-3 square contains only one instance of each number; also written sudoku
Examples

Sudoku has joined crosswords in most newspapers.
Word Origin

1980s
noun

See Sudoku