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
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