A rhombus is a four-sided shape where all four sides are exactly the same length, but unlike a square, its corners usually aren't right angles. If you took a square and pushed on two opposite corners until it leaned over sideways, you'd create a rhombus. The shape looks like a diamond on a playing card or a tilted square.

Think of a rhombus as a parallelogram (a shape where opposite sides are parallel) that happens to have all its sides equal. Because of this, a rhombus has some interesting properties: opposite angles are equal to each other, and if you drew lines connecting opposite corners, those lines would cross at right angles at the center.

You'll see rhombuses in tile patterns, quilts, and geometric art.

Every square is technically a rhombus (since all four sides are equal), but not every rhombus is a square. That's because a square has the extra requirement of right angles at every corner.