coul·ter or col·ter (kōltər)
A blade or wheel attached to the beam of a plow that makes vertical cuts in the soil in advance of the plowshare.
[Middle English culter, from Old English culter and Old French coltre, both from Latin culter, knife, plowshare; see skel-1 in the Appendix of Indo-European roots.]
(click for a larger image)coulter
round coulter blade (left) in front of a moldboard
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.