Circumference

In geometry, the circumference (from Latin circumferentia, meaning “carrying around”) of a circle is the (linear) distance around it. That is, the circumference would be the length of the circle if it were opened up and straightened out to a line segment. Since a circle is the edge (boundary) of a disk, circumference is a special case of perimeter. The perimeter is the length around any closed figure and is the term used for most figures excepting the circle and some circular-like figures such as ellipses.

Informally, “circumference” may also refer to the edge itself rather than to the length of the edge.

**Wikipedia**

Circumference (noun)

The line that bounds a circle or other two-dimensional figure

Circumference (noun)

The length of such a line

Circumference (noun)

The surface of a round or spherical object

Circumference (noun)

The length of the longest cycle of a graph

Circumference (verb)

To include in a circular space; to bound.

Girth (noun)

A band passed under the belly of an animal, which holds a saddle in place.

Girth (noun)

The part of an animal around which the girth fits.

Girth (noun)

One’s waistline circumference, most often a large one.

Girth (noun)

A small horizontal brace or girder.

Girth (noun)

The distance measured around an object.

Girth (noun)

The length of the shortest cycle in a graph.

Girth (verb)

To bind as if with a girth or band.

**Wiktionary**

Circumference (noun)

the enclosing boundary of a curved geometric figure, especially a circle.

Circumference (noun)

the distance around something

“babies who have small head circumferences”

“a rope two inches in circumference”

Girth (noun)

the measurement around the middle of something, especially a person’s waist

“an ivy-clad tree of immense girth”

“a pike with a girth of 24 inches”

“idle men of great girth”

Girth (noun)

a person’s waist or stomach, especially when large

“he tied the knotted towels around his girth”

Girth (noun)

a band attached to a saddle and fastened around a horse’s belly to keep the saddle in place.

Girth (verb)

surround; encircle

“the four seas that girth Britain”

**Oxford Dictionary**