The term 'eight sided' can be described by two words: octagon (7 letters) and octagonal (9 letters). An octagon is a polygon with eight sides and eight angles. It is a two-dimensional shape that is often used in architecture, such as in the design of windows or doors. Octagonal shapes are also found in nature, such as in the shape of some flowers. Octagonal shapes can also be found in three-dimensional objects, such as in the shape of some crystals.