This is the 398th most frequent German word.
stefan
"Stefan" is a German male given name, equivalent to "Stephen" or "Steven" in English.
In this sentence, 'Stefan' is used as the subject of the verb 'liest'.
Stefan liest gern Bücher.
Stefan likes reading books.
Here, 'Stefan' is used as a possessive noun indicating the owner of the book.
Das ist das Buch, das Stefan gehört.
This is the book that belongs to Stefan.
In this usage, 'Stefan' is the indirect object of the verb 'frage'.