sudoku

noun

1. (countable, uncountable)A type of pencil puzzle played on a square grid, requiring each of the columns, each of the rows, and each of the subregions (called "boxes" or "regions") to contain the lowest whole numbers up to the dimension of the puzzle, usually 1 to 9, once each. The subregions are rectangular or square except in variants.

   “For Preston is the publishing director at Puzzler Media, which creates magazines filled with puzzles, including one called sudoku that has taken Britain by storm. […] The puzzles are widely available over the Internet because efforts to trademark the name in Britain have not been successful, and you can even download sudokus to mobile phones.”

   “In fact, anything we do just to kill time—even essentially healthy activities like reading, chatting on the phone, or completing a sudoku puzzle—becomes a 'time thief.”

   “The annual championship event comprises two days of Sudoku, followed by three days of other types of pencil-and-paper logic puzzles. Some of the Sudokus were classics: In a 9-by-9 grid, insert a number from 1 to 9 into each cell so that no number repeats in any row, column or bolded 3-by-3 square region.”