Think of the space you stand in after the outer door has closed behind you but before the inner door opens. It has walls and doors of its own, and it may have a or a mat, yet nobody stays in it. It is there to hold the outside one step away from the inside.
vestibule 可以想成「已經進門、還沒到裡面」的那一塊空間。你推開外面那道門，站定，把身上的雨拍掉，然後才打開第二道門真正走進去。它有牆、有門，有時候還有公布欄，但沒有人會在那裡久留。它存在的理由，就是把外面和裡面隔開一段距離。
From the word’s history
The source records it as borrowed in the early 17th century from French vestibule, from Latin vestibulum, meaning a forecourt or entrance court. The oldest meaning is the same picture the word still carries: the ground you cross before you are properly inside.
來源記載這個字在十七世紀初從法文 vestibule 借入，再往上是拉丁文 vestibulum，意思是「屋子前面的院子、入口」。也就是說，它最早講的就是今天的核心畫面：還沒真正進屋、但已經不在外面的那塊地方。
Wiktionary (kaikki extract, source_ref kaikki:3f6f69a190036ae4:842920072:53698)
登入就可以看每一支怎麼連回核心畫面。