the world > space > shape > curvature > roundness > [adjective] > circular > of or relating to or forming circumference (3)
Of, pertaining to, or of the nature of the circumference.
Forming the circumference, encircling, encompassing; travelling around.
Of a measurement: made of the circumference (or occasionally diameter) of a circular, cylindrical, or spherical object, esp. a piece of timber.