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
    see moresee less
    type of:
    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
    see moresee less
    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
    see moresee less
    the distance around a person's body
    the expansion of a person's girth (especially at middle age)
    type of:
    the physical magnitude of something (how big it is)
Word Family

Test prep from the experts

Boost your test score with programs developed by’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week