su·do·ku 
(s-dōk)
(s-dōk)n.
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.
[Japanese sūdoku, contraction of sū(ji wa) doku(shin ni kagiru), the numbers are limited to a single occurrence (the phrase under which sudokus appeared in a magazine which popularized them in Japan in the 1980s) : sū(ji), number + doku(shin), single.]
- infract
- infraction
- infractor
- infra dig
- infrahuman
- infrangibility
- infrangible
- infrangibly
- infraorder
- infrared
- infrared astronomy
- infrasonic
- infrasound
- infraspecific
- infrastructural
- infrastructure
- infrequence
- infrequency
- infrequent
- infrequently
- infringe
- infringement
- infringer
- infructescence
- in full cry