This is the 699th most frequent Croatian word.
otac
Father.
'Otac' is used as a standard singular noun referring to one's father.
Moj otac voli čitati knjige.
My father loves reading books.
Here, 'otac' refers to the legal relationship of fatherhood.
On je moj otac po zakonu.
He is my father by law.
In this context, 'otac' denotes the head patriarchal figure of the family.