A plough, or plow, is a farming tool, used to till furrows into the earth. It’s a period charge, found in the arms of Smeton, c.1460 [RH]. The plow is fesswise, handles to sinister by default.
The illustration is taken from Bossewell, 1572 [II.124].
Alan the Strong bears: Or, a plow vert and on a chief embattled sable three garbs Or.
Beatrix of Thanet bears: Per fess enarched azure and vert, three garbs and a plough Or.
Johannes von Narrenstein bears as a badge: A quill pen argent, tip surmounted by a wooden plow proper.