They were called Tetrads in the original Tetris manual for Game Boy and the NES.
They were also called tetrads in a random zing in the NES game Zoda's Revenge: StarTropics 2, as can be seen here:
At some point the switch was made from "Tetrads" to "Tetriminoes" and they are called Tetriminoes in Tetris DS. I'm not sure when the switch was made, but I remember seeing "Tetriminoes" in the manual for Tetris DS and wondering what the hell happened.
Also, a quick look at Wikipedia tells me that "tetrominoes" is the original word which comes from the Greek "tetra" and "domino" but that the Tetris Company spells it with an I instead of an O.
Apparently I'm the only one using either term because I'm the only person here who gives a shit about Tetris vocabulary. I'm ashamed of all of you.












