umstroke

In obsolete|lang=en terms the difference between circumference and umstroke

is that circumference is (obsolete) the surface of a round or spherical object while umstroke is (obsolete) the circumference or periphery of a circle.

As nouns the difference between circumference and umstroke

is that circumference is (geometry) the line that bounds a circle or other two-dimensional figure while umstroke is (obsolete) the circumference or periphery of a circle.

As a verb circumference

is (obsolete|transitive) to include in a circular space; to bound.