1. The boundary line of a circle.
a. The boundary line of an area or object.
b. Abbr. c or circ. The length of such a line.
3. The margin or area surrounding something.
[Middle English, from Old French circonference, from Latin circumferentia, from circumferēns, circumferent-, present participle of circumferre, to carry around : circum-, circum- + ferre, to carry; see bher-1 in the Appendix of Indo-European roots.]
cir·cum′fer·ential (-fə-rĕnshəl) adj.
Synonyms: circumference, circuit, compass, perimeter, periphery
These nouns refer to a boundary or area around the outer edge of something: drove around the circumference of the city; followed the circuit around the park; stayed within the compass of the schoolyard; walked the perimeter of the estate; fenced the periphery of the property.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.