circumference

/sərˈkʌmfərəns/

/səˈkʌmfrəns/

Other forms: circumferences

The distance around a circle is called the circumference, and although circumference is often used when talking about round things, it can mean a boundary of any shape that completely surrounds something.

It’s no coincidence that the first part of circumference looks like circle. The Latin word circum means “around,” and the root ferre is the Latin verb for “carry,” so imagine carrying a puppy around a circle pit of lava: the path you walk is the circumference. If you want to buy a new hat, you’ll need to measure the circumference of your head, and patrolling the circumference of your castle is a good way to protect against dragons.

Definitions of circumference

1. noun

   the length of the closed curve of a circle
   type of:

   length

   the linear extent in space from one end to the other; the longest dimension of something that is fixed in place
2. noun

   the boundary line encompassing an area or object
   “he had walked the full circumference of his land”

   “a danger to all races over the whole circumference of the globe”

   synonyms: circuit

   type of:

   border, borderline, boundary line, delimitation, mete

   a line that indicates a boundary
3. noun

   the size of something as given by the distance around it
   synonyms: perimeter

   types:

   girth

   the distance around a person's body

   spread

   the expansion of a person's girth (especially at middle age)

   type of:

   size

   the physical magnitude of something (how big it is)