Final answer:
A hexagon is the shape with six sides found in a beehive; it is a flat, two-dimensional polygon that makes up the cells of a honeycomb.
Step-by-step explanation:
The shape that has six sides and is also found in a beehive is called a hexagon. This geometric figure is a flat, two-dimensional shape with straight lines. In the context of a beehive, the hexagonal shapes are the individual cells of the honeycomb structure where bees store honey and pollen and where the queen lays eggs. Contrary to the mentioned octahedron and icosahedron which are three-dimensional solids, the hexagon relevant to the question is a two-dimensional polygon.