九ちゅーMeanings1numericnineUsed in mahjong to refer to the number nine. The reading チュー is derived from Chinese jiǔ. Other mahjong readings include クー and キュー.from Chinese jiǔ麻雀まーじゃんで「チュー」は九ちゅーを意い味みする。In mahjong, 'chū' means nine.