circumscribes

Circumscribes is the form of circumscribe used to describe drawing a boundary around an object or area, or surrounding it with another figure. In geometry, circumscribe often refers to enclosing a figure with a larger figure in such a way that the inner figure touches the outer one at specific points.

A central geometric concept is the circumcircle. A circle that passes through all vertices of a polygon is called a circumcircle, and the polygon is inscribed in the circle while the circle circumscribes the polygon. Every triangle has a circumcircle, whose center is the circumcenter and which is found at the intersection of the triangle’s perpendicular bisectors. A set of points that cannot all lie on a single circle has no circumcircle.

The reverse situation involves a circle inscribed in a polygon. If a polygon is circumscribed about a circle, then every one of its sides is tangent to that circle; the circle is the polygon’s incircle, and the polygon is tangential or circumscribed about the circle. For quadrilaterals, a classic condition for tangentiality is that the sums of the lengths of opposite sides are equal.

Beyond geometry, circumscribes can be used in a broader, non-technical sense to mean enclosing, surrounding, or limiting something within defined boundaries. In any context, the term emphasizes the idea of outlining or enveloping the object from the outside.