Questions & Answers about Hulen er mørk.
In Norwegian, the definite article is usually attached to the end of the noun instead of standing as a separate word.
So:
- hule = cave
- hulen = the cave
The ending -en is functioning like English the here.
The dictionary form is hule.
That is the basic indefinite singular form, the form you would look up in a dictionary. From that, Norwegian builds other forms, such as:
- en hule / ei hule = a cave
- hulen / hula = the cave
Yes, hule is traditionally a feminine noun, but in Bokmål many feminine nouns can also be used with masculine forms.
So both of these can be correct in Bokmål:
- hula = the cave
- hulen = the cave
A learner will often see both. Hulen is not wrong; it is just using the masculine-style definite ending.