This is the 748th most frequent Slovenian word.
oče
Father.
Here, 'očetu' is the dative form of the noun 'oče', used as the indirect object in the sentence.
Govorili smo o očetu in njegovem delu.
We talked about the father and his work.
In this context, 'oče' again means 'father', used as the subject of the sentence referring to someone else's male parent.
Njegov oče me je povabil na večerjo.
His father invited me to dinner.
In this sentence, 'oče' means 'father', used to denote one's male parent.