n. a circle inscribed in a triangle so that each of the sides of the triangle is a tangent, of which the center is the incenter, and the radius is the inradius. The figure shows the construction of the incircle: the center is the point of intersection of the bisectors of the angles of the given triangle, and the radius is the perpendicular from that point to any side. Compare circumcircle.
O is the incenter and OR the inradius of ABC.