Questions & Answers about Orðabókin sem ég nota er góð.
Because -in is the definite article attached to the noun.
- orðabók = dictionary
- orðabókin = the dictionary
In Icelandic, the is usually not a separate word like in English. It is very often added to the end of the noun.
Also, orðabók is a feminine noun, and -in is the nominative singular definite ending here.
You generally have to learn the gender of each noun as part of the word.
In this sentence, you can tell it is feminine because of the forms around it:
- orðabókin has a feminine definite form
- góð is the feminine singular form of góður (good)
So the adjective is agreeing with orðabókin, which shows that the noun is feminine.
Sem introduces a relative clause. It works like that, which, or who in English, depending on context.
So in:
- Orðabókin sem ég nota...
the word sem connects the dictionary with the extra information I use.
It is the word that links the noun to the clause describing it.