1) Agricultural machinery 2) Colter 3) English boy name 4) Wedge 1) Colter 
iron cutter in front of a ploughshare
• (n.) Same as Colter.
Coul'ter (kōl'tẽr) noun Same as Colter . 
A coulter or colter is the sharp fore iron (vertical cutting blade) fixed in front of the share of a plough and used for cutting the sod or earth.
coulter 1. A blade or wheel attached to the beam of a plow that makes vertical cuts in the soil in advance of the plowshare. 2. From Middle English culter, from Old English culter, and Old French coltre; all come from Latin culter, 'knife, plowshare'.
That part of a seed drill which actually works in the soil to place and cover the seed. They may be of the disc type or shoe type.