This is the 16571st most frequent Korean word.
사립문은
"사립문은" means "a (small) private gate."
사립문은 refers to 'private gate,' functioning as the subject of the sentence.
사립문은 닫혀 있습니다.
The private gate is closed.
Here, 사립문은 specifies the object being referred to in the context of opening it.
사립문은 손으로 열어야 합니다.
You must open the private gate by hand.
In this sentence, 사립문은 is used to indicate the subject that was open.