A rhombus is the shape of a square after somebody stepped on it and bent it.
Yes. It's easiest to see how by working backwards. Draw a rhombus, then draw a line between two opposite corners. Poof! You have two triangles.
The rhombus is a quadrilateral - 4-sided polygon - in which all 4 sides have the same length. Among other things, this leads to the following additional properties:Opposite sides are parallelOpposite angles are congruentDiagonals cross one another at a right angleDiagonals bisect one another