Ploughshare

In agriculture, a plowshare (US; /ˈplaʊ.ʃɛər/) or ploughshare (UK; /ˈplaʊ.ʃɛər/) is a component of a plow (or plough). It is the cutting or leading edge of a moldboard which closely follows the coulter (one or more ground-breaking spikes) when plowing.

The plowshare itself is often a hardened blade dressed into an integral moldboard (by the blacksmith) so making a unified combination of plowshare and moldboard, the whole being responsible for entering the cleft in the earth (made by the coulter's first cutting-through) and turning the earth over.

In well-tilled terrain the plowshare may do duty without a preceding coulter.

In modern plows both coulter and plowshare are detachable for easy replacement when worn or broken.

Plowshares are often used in heraldry.

Arms of Erding

Arms of Tunau

Arms of Leuna

Arms of Erlbach

...
Wikipedia