This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. A curved blade on a plough that serves to turn over the furrow

n. A follow board.

n. wedge formed by the curved part of a steel plow blade that turns the furrow

"- The mouldboard is the other main part of the plow which turns over the earth previously cut by the courter and the share."

wedge   

moldboard