A hermetically sealed container or space is so tightly closed that no air can leave or enter it.

separated and protected from very different conditions outside, in an unnatural way

We drove past a row of squalid shacks on the way to our hotel, where we slept in air-conditioned, hermetically sealed rooms. 我们开车驶过一排肮脏的棚屋，回到我们下榻的宾馆，在开着空调、完全封闭的房间里上床就寝。