Triomino

Part of speech: noun

Definitions

1. A flat game piece made of three squares joined edge to edge, used in certain tiling and board puzzles
2. A three-square tile shape employed in games and puzzles where pieces are arranged to cover a board
3. Any polyomino built from exactly three equal squares connected along their sides, used as a playing piece

Etymology: "Triomino" is a playful blend of the Latin-derived prefix "tri-", meaning "three", with "domino", the name of the familiar game piece. A triomino is a shape made from three equal squares joined edge to edge, and the word follows the same logic as "domino", which likely came from the pattern of dots on the tiles. The word is a recent coinage, built from a numeric prefix and an existing game term, in the same way that "tetromino" and "pentomino" name shapes of four and five squares. The second element is often given as "-omino" rather than "domino", reflecting the fact that the shape-naming pattern is a family of formations built on a shared ending. Both forms of the word describe the same idea: a set of squares arranged together, with the number of squares given by the prefix. Because the word was built from familiar parts rather than inherited from an older language, its meaning is transparent to anyone who knows what a domino is.