This is the 15699th most frequent Russian word.
приоткрытое
Slightly open.
Here 'приоткрытое' means 'slightly opened,' describing the state of the window being partly open.
Я открыл приоткрытое окно, чтобы впустить свежий воздух.
I opened the slightly opened window to let in fresh air.
In this case, 'приоткрыта' indicates the door is not fully closed, allowing sound to travel.
Дверь была приоткрыта, и я услышал разговор внутри комнаты.
The door was slightly ajar, and I heard the conversation inside the room.
Here 'приоткрытую' describes the curtain being adjusted to leave a small gap for visibility.