Haddock is a surname of English. It may refer to many people.
It may come from the medieval word Ædduc, a diminutive of Æddi, a short form of various compound names including the root ēad, meaning prosperity or fortune.
It may also refer to someone who comes from Haydock, a town near Liverpool. "Haydock" probably comes from the Welsh word heiddog, meaning "characterized by barley".
It may also come from Middle English hadduc, referring to someone who worked as a fisherman or a fish seller, or who looked like a fish. [1]