cod

The origin of the word 'cod' for the fish is obscure but is thought to have entered Middle English from a Germanic language, possibly related to the Old Norse word 'koddi', meaning 'pillow' or 'cushion', perhaps alluding to the fish's shape. The term became firmly established in English to denote this specific type of fish, particularly the Atlantic cod (Gadus morhua), which was a cornerstone of the medieval European economy. The informal, now largely archaic, meaning of 'a hoax or joke' (as in 'to cod someone') emerged in the 19th century, possibly from the verb 'cod' meaning 'to hoax' or 'to fool', whose own origins are similarly uncertain but may be unrelated to the fish.

The word 'cod' is a simplex word of uncertain origin, likely from a Low German or Scandinavian source (e.g., Middle Low German 'kabeljau', Danish 'torsk'). Its role is as a monomorphemic noun root.