A polyomino is a plane geometric figure, connected, formed by joining a finite number of unit squares edge-to-edge. It is a polyform whose cells are squares. It may be regarded as a finite and connected subset of the regular square tiling.
Polyominoes have been used in popular puzzles since at least 1907, and the enumeration of pentominoes is dated to antiquity. Many results with the pieces made of 1 to 6 squares were first published in Fairy Chess Review between the years 1937 and 1957, under the name of "dissection problems." The name polyomino was invented by Solomon W. Golomb in 1953, and it was popularized by Martin Gardner in a November 1960 "Mathematical Games" column in Scientific American.
