市門 is read as しもん (shimon) and means city gate.
しもん
shimon
もんぜんいちをなす
to have many visitors (of a home)
もんぜんせいし
having a constant stream of visitors
しはん
putting on the market
しちょうそん
cities, towns and villages
しえい
(under) municipal management (transport, housing, etc.)
しきょう
market conditions
しじょうちょうさ
market research
しちょう
municipal office
しえいちかてつ
municipal subway
しじょうくぶん
market segment
しく
municipal district
しみんぐん
militia