Original: The moulding plane, which is used to cut mouldings along the edge of a board The rabbet plane, also known as a rebate or openside plane, which cuts rabbets (rebates) i.e. shoulders, or steps.
Simplified: The moulding plane, which is used to cut mouldings along the edge of a board The rabbet plane, also known as a rebate or openside plane, which cuts rabbets (shoulders, or steps) and dadoes.