Obviously, the name of the game is derived from the term "tetramino". This is how the figure made of 4 connected squares is called.Originally Posted by TATY
The word "tetramino" is not of Russian origin, also. Most probably, it is borrowed from some book written by Martin Gardner. (His books were very popular and wide known in Soviet Union, BTW.)
Yes, game of Tetris was invented in SU. But, I have serious doubts, whether Alexey Pazhitnov was actual inventor. The actual idea was known (and implemented lots of times) years before his Tetris.