своей комнаты

one's room

→ свой
phrase Rare #43,688
one's room The genitive singular form of своя комната. Своей refers back to the subject of the sentence, so it can mean “his,” “her,” or “their” room depending on context.
RU: Она не может найти ключ от своей комнаты.
EN: She can't find the key to her room.