Haddock
Likely a habitational surname from Haydock in Lancashire, though older writers also tried to link it to nicknames or personal names.
The #4,472 most common surname in the United States (2010 Census) — about 1 in every 38,885 Americans shares it.
Etymology
The strongest traditional explanation is that Haddock is a variant of Haydock, the name of a place in South Lancashire. In that view, the surname began as a label for someone who came from that locality. Some 19th-century writers proposed other origins, including a personal-name source or a derivation from older forms such as Hadeca/Hadiko, but these are less secure.
History
Bardsley treats Haddock as essentially the same as Haydock, and Lower also says it is unlikely to come from the fish name. Charnock offered a more speculative personal-name derivation, but that view was already uncertain in his day. In modern surname work, the place-name explanation is generally the safest.
Origin
Regions
Variant spellings
Fun fact
Some older surname books file Haddock among so-called “fish-names,” but most of them thought that resemblance was misleading.
From the historical record
“HADDOCK surviving in the surname Seaman, q.v. But this ' Norse extraction ' is no better nor worse than a hundred conjectures in print at this moment Cf. Haconby, a parish in Co. Line Mr. Freeman (Norman Conquest, iii. 919) writes, under date 105a, * According to another account, Godwine, on his recon- ciliation…”
— A Dictionary of English and Welsh Surnames (alternate scan)