Learn Hardcore Norwegian: Semesteret slutter før ferien. - The semester ends before the vacation.

Semesteret is the definite form, meaning "the semester." In Norwegian you don’t use a separate word for “the” at the end. Instead, neuter nouns like semester take the suffix -et to show definiteness. The indefinite form would be et semester (“a semester”).

How do I form the definite singular of a neuter noun like semester?

To make a neuter noun definite in Norwegian:

Start with the indefinite form: et semester.
Drop the article et and add -et to the noun: semester → semesteret.
This pattern holds for most neuter nouns: et hus → huset, et brev → brevet.

Why is ferien used instead of ferie or en ferie?

Here we refer to the holiday or the vacation that follows the semester. Ferie is a feminine noun:

Indefinite: en ferie (“a holiday”)
Definite: ferien (“the holiday”)
Since we’re talking about a specific break, we use the definite form ferien.

What part of speech is in this sentence—preposition or conjunction?