1. Rectangle
2. Cuboid
3. Rhombus
4. Quadrilateral
5. Parallelogram
6. Trapezoid
7. Pentagon
8. Hexagon
9. Octagon
10. Cube
11. Oblong
12. Solid
13. Regular
14. Plane
15. Symmetrical
16. Regular Polygon
17. Right-angled
18. Even-sided
19. Flat
20. Four-sided
21. Geometric
22. Equiangular
23. Isosceles
24. Plane Figure
25. Angular
26. Balanced
27. Biquadratic
28. Orthogonal
29. Quadrate
30. Symmetric

When looking for synonyms for the word «square», the best ideas are to think of other words for the term that are related to its shape and geometry. A square is a four-sided, symmetrical, regular polygon with all sides of equal length and all angles of 90 degrees. Other words for square include rectangle, cuboid, rhombus, quadrilateral, parallelogram, trapezoid, pentagon, hexagon, octagon, cube, oblong, solid, regular, plane, symmetrical, regular polygon, right-angled, even-sided, flat, four-sided, geometric, equiangular, isosceles, plane figure, angular, balanced, biquadratic, orthogonal, quadrate, and symmetric. Each of these terms can be used to describe the shape of a square.