This is the 41st most frequent Azerbaijani word.
onun
"His," "her," or "its" (possessive pronoun).
"Onun" indicates possession and association, referring to the favorite color of the person being discussed.
Bu onun sevdiyi rəngdir.
This is his/her favorite color.
"Onunla" is a derived form of "onun," combined with the suffix "-la/-lə" (with), indicating 'with him/her.'
Axşam onunla görüşəcəyik.
We will meet with him/her in the evening.
"Onun" shows possession, indicating that the book belongs to him or her.