The shape (from Old English ȝesceap, shap, etc., originally meaning created thing) of an object located in some space is the part of that space occupied by the object, as determined by its external boundary – abstracting from other properties such as colour, content, and material composition, as well as from the object's other spatial properties (position and orientation in space; size).
Mathematician and statistician David George Kendall defined shape this way:[1]
Shape is all the geometrical information that remains when location, scale and rotational effects are filtered out from an object.
Simple two-dimensional shapes can be described by basic geometry such as points, line, curves, plane, and so on. (A shape whose points belong all the same plane is called a plane figure.) Most shapes occurring in the physical world are complex. Some, such as plant structures and coastlines, may be so arbitrary as to defy traditional mathematical description – in which case they may be analysed by differential geometry, or as fractals.
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