Mid 17th century; earliest use found in Walter Blith (bap. 1605, d. 1654), writer on husbandry. Either from earth + board or perhaps from earth + board.
Definition of earthboard in US English:
earthboard
nounˈəːθbɔːd
Mouldboard.
Origin
Mid 17th century; earliest use found in Walter Blith (bap. 1605, d. 1654), writer on husbandry. Either from earth + board or perhaps from earth + board.