門戸 is read as もんこ (monko) and means door.
もんこ
monko
もんこかいほう
open door policy
もんこをひらく
to open the door (to the world, women, etc.)
もんこをとざす
to close the door (to)
もんこかいほうせいさく
もんこをはる
to keep a fine house
みとこうもん
Mito Kōmon (televised period drama; 1969-2011)
もん
branch of learning based on the teachings of a single master
と
door (esp. Japanese-style)
かどで
starting a new life
もんぜんまち
town originally built around a temple or shrine
もんかせい
pupil
もんがいかん
outsider