A polyomino of $n$ squares can be referred to as an $n$-omino.
That is, it is considered free of the plane in which it is embedded, and can be "lifted up and turned over".
Also known as
An $n$-omino can also be referred to by the more unwieldy name $n$-polyomino.
For small $n$, polyominoes have their own names:
- $n = 1$: Monomino
- $n = 2$: Domino
- $n = 3$: Tromino
- $n = 4$: Tetromino
- $n = 5$: Pentomino
- $n = 6$: Hexomino
- $n = 7$: Heptomino
- $n = 8$: Octomino
- Results about polyominoes can be found here.
The plural of polyomino is polyominoes.