For over two decades, the puzzle video game Tetris has provided countless hours of procrastination and enjoyment for players all over the globe.

But now, researchers believe that Tetris might have a new purpose. They think that the game may help to prevent the flashbacks that occur in the early stages of post-traumatic stress disorder.

While the research is fascinating, let’s turn our attention to the word. What does Tetris mean?

While working at the Academy of Science of the USSR in Moscow, Alexey Pajitnov designed and programmed Tetris, which was released in 1984. Many consider it to be the greatest game of all time. Over a hundred million copies of the game have been sold for cell phones alone.

Pajitnov derived the name Tetris by combining Greek with the name of his favorite sport. Tetra is a Greek numerical prefix meaning “four,” and tennis was the game designer’s sport of choice.

(Tetra is also any of the tropical freshwater fishes of the genus Hemigrammus.)

The premise of the game is fairly simple. Random sequences of tetrominoes, or tetrads, fall onto a playing field. (A geometric shape made up of four squares that are connected orthogonally is called a tetromino, which is also called a tetramino or tetrimino.) The player then manipulates these tetrominoes, aiming to create a horizontal line of blocks without gaps. The player continues to create these lines, and with every ten that are created, the game enters a new level and becomes more challenging.

Since we mentioned tennis, do you know “why love” is used as a term for the score?