入口

entrance / to import

to enter / to go into / to join / to become a member of / to confirm or agree with / abbr. for 入聲|入声[ru4 sheng1]

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

to melt in one's mouth

Web portal / (enterprise) portal

web portal

gateway

boarding gate