"Tetris (Russian: Те́трис) is a puzzle video game originally designed and programmed by Alexey Pazhitnov in the Soviet Union. It was created on June 6, 1984, while he was working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow. He derived its name from the Greek numerical prefix "tetra- (all of the game's pieces, known as Tetrominoes, contain four segments) and tennis, Pazhitnov's favorite sport.
The Tetris game is a popular use of tetrominoes, the four element special case of polyominoes. Polyominoes have been used in popular puzzles since at least 1907, and the name is given by the mathematician Solomon W. Golomb in 1953. However, even the enumeration of pentominoes is dated to antiquity."
Source: Wikipedia, "Tetris", available under the CC-BY-SA License.