This is the 111th most frequent Norwegian word.
tillegg
Addition; supplement.
Here, 'i tillegg' connects items in a list, showing addition.
Vi må inkludere dette i tillegg til det andre.
We need to include this in addition to the other.
In this sentence, 'i tillegg' is used as an adverbial phrase indicating 'in addition to' or 'as well as'.
I tillegg til å studere, jobber han deltid.
In addition to studying, he works part-time.
In this example, 'tillegg' is a noun meaning 'an addition' or 'something supplemental'.