a. A closed line bounding a plane area.
b. The length of such a line.
2. The outer limits of an area. See Synonyms at circumference.
3. A defended boundary protecting a military position.
4. Basketball The three-point line.
[Middle English perimetre, from Latin perimetros, from Greek : peri-, peri- + metron, measure; see METER2.]
per′i·metric (pĕr′ə-mĕtrĭk), per′i·metri·cal (-rĭ-kəl) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. 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.