For the slang term, please see square.
A square is a specific type of tetragon which had four equal sides. A cube is composed of six squares.
In 2374, Miles O'Brien mistook Vic Fontaine's usage of the slang term "square" for one side of a cube. (DS9: "His Way")
In 2376, Icheb created a twenty six-sided polyhedron out of clay, composed of hexagons, octagons, and squares. Seven of Nine was impressed by Icheb's work. (VOY: "Ashes to Ashes")