Questions & Answers about Sluken har en fiskekrok.
Because -en is the usual ending for a definite singular masculine noun in Norwegian.
- en sluk = a lure / a spoon lure
- sluken = the lure
So Sluken har en fiskekrok uses the definite form because it is talking about the lure, not just a lure.
Because en fiskekrok is indefinite singular: a fish hook / a fishing hook.
- en fiskekrok = a fishing hook
- fiskekroken = the fishing hook
So the sentence contrasts:
- sluken = the lure
- en fiskekrok = a fishing hook
In other words, it is talking about a specific lure that has a hook.