vomer

The vomer or ploughshare is the cutting part of the plough ( the aratrum), which digs into the earth and makes furrows for sowing seeds and planting. Used by the Greeks and Romans from very early times, it was originally made entirely of wood, but the vomer came to be made of metal or covered in metal for greater strength (see farming implements, including the plough, used by the Egyptians during the Roman period; see also British farming under the Romans, including a view of the plough).
The vomer is in the list of farm tools about which Pliny the Elder speaks in Naturalis Historia, in his narration of the self-defense of Gaius Furius Chresimus, a freed slave and small farm owner, who was indited by the curule aedile Spurius Albinus for casting spells on his wealthy neighbors' estates.
Juvenal lists the vomer in a later satire (Satura 15.167), where he again employs the metaphor of farming implements to reprise the theme of the violence of contemporary Rome.