Questions & Answers about Hundagjaldið er hátt.
It is a compound noun plus the definite article:
- hunda- = dog-related first element
- gjald = fee, charge
- -ið = the for a neuter singular noun
So hundagjaldið is built from hundagjald + -ið.
In Icelandic compounds, the first noun often does not stay in its basic dictionary form.
The dictionary form is hundur = dog, but in compounds you often get a linking form such as hunda-. So hundagjald is the normal compound form, not hundurgjald.
This is very common in Icelandic, and it is something learners usually have to get used to rather than predict perfectly every time.
Because Icelandic usually adds the definite article to the end of the noun instead of using a separate word.
So:
- hundagjald = a dog fee / dog fee
- hundagjaldið = the dog fee
That final -ið is doing the job of English the here.