1. Grammar A punctuation mark ( , ) used to indicate a separation of ideas or of elements within the structure of a sentence.
2. A pause or separation; a caesura.
3. Any of several nymphalid butterflies of the genus Polygonia having wings with irregularly notched edges and a small comma-shaped marking on the underside of the hind wing.
[Latin, from Greek komma, piece cut off, short clause, from koptein, to cut.]
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.