Definition of "sudoku" [sudoku]

• A puzzle in which a grid consisting of several regions is to be filled with numbers so that every row, column, and region contains only one instance of each number. The most common format is a grid of nine rows and columns that are divided into nine smaller regions of three rows and three columns into which the numbers 1 through 9 must be placed. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "For everybody who wants to try out something new in sudoku, try shendoku, using the sudoku rules but playing two people, one against the other, like battleshipps."
• "Logic games are popular in Japan largely due to the work of Nikoli, which was founded 27 years ago, but sudoku is the only one known abroad."
• "So I will post two links a day, one to the daily killer, and one to an interactive plain sudoku on the same site (as you can't get an interactive killer free on that site)."