coulter

noun2

1. •
   A cutter, consisting of a blade in either knife form or disk form, attached to the ploughbeam of a plough to cut the sward, in front of the ploughshare and mouldboard.

   • I lately left a furrow, one or twayne, / Unplough'd, the which my coulter hath not cleft […]. — 1596
2. •
   (UK) The part of a seed drill that makes the furrow for the seed.