Medical Definition of Snellen chart. : the chart used in the snellen test with black letters of various sizes against a white background.
The circumcenter, the incenter is the point of concurrency of the angle bisectors of a triangle.
A point of concurrency is a place where three or more, but at least three lines, rays, segments or planes intersect in one spot. If they do, then those lines are considered concurrent, or the the rays are considered concurrent. So let's look at two examples here.