A rhombus has only two lines of symmetry. A rhombus is a four-sided, two-dimensional shape, also called a diamond, that falls under the category of quadrilaterals. Its sides are the same length, but angles are not 90 degrees.
A line of symmetry is a plane that can be drawn through a two-dimensional figure to yield two perfectly mirrored sides. If the shape was folded over the line, all of the edges on either side would match up exactly. A rhombus has two lines of symmetry that run through one vertex to the one directly across it. Unlike a square, planes through the center of each edge of a rhombus do not yield mirrored sides.