Etymology
From Middle English haddok. Compare Anglo-Norman hadoc from Old French hadot, probably from an English source. Further origin uncertain, but hadot could have evolved from (h)adoux, (h)adoz, from adoub, from adouber, adober (“to prepare”), cognate with Italian addobbare (“to souse fish or meat”). The spelling is usually regarded as a diminutive in -ok (see -ock).
Definitions & examples from Wiktionary (CC BY-SA 3.0).