I asked a coworker the other day to put something in the vestibule, a small room that connects two other rooms. He, and a few others, didn’t know what I meant since they had never heard this word before. I suddenly felt like Henry Higgins. I suppose it isn’t used very often, and I suspect it is something I picked up in church when I was young. A vestibule is a small connecting room, ante-chamber or lobby, such as cathedrals often have. You may also have heard it in relation to the ear, usually in the form vestibular, as this part of the ear is a connecting area to several others. The word comes to us directly from Latin, where it referred to a courtyard.
Curiously, it has no relation to another church-related word, vestment (a ceremonial garment), though I was surprised to learn that one of the definitions of invest is to clothe or adorn. Both of these have the same Latin origin. However, the usual meaning of this word, to expend resources for gain, is unrelated and comes to us from Italian – another case of a word having several different meanings largely because it came to us from different languages or sources. You could argue that to invest in something results in one being adorned with benefits. Just because there is no recorded connection between words’ various meanings doesn’t mean that one isn’t there. It is even possible that vestments were once put on in vestibules, which, in the church setting, makes sense to me.