noun
Often used figuratively for an entrance or opening, especially in phrases like 門戸を開く (open the door to) or 門戸を閉ざす (shut the door on).
大学は社会に門戸を開いている。
The university is open to the community.
その国は外国企業に門戸を閉ざした。
The country shut its doors to foreign companies.