Yes. Revoir is the infinitive form of a verb meaning to see again.
It is built from:
So revoir literally means to see again.
In Au revoir, you do not need to analyze it every time you use it; native speakers treat Au revoir as a normal fixed goodbye expression.
No. The exclamation mark is optional.
You can write:
The version with ! feels a bit warmer, more lively, or more expressive. In normal writing, both are fine depending on tone.
Yes. Au revoir is not tied to a specific time of day.
You can use it:
Unlike greetings such as Bonjour or Bonsoir, Au revoir works as a general goodbye.
Not really for everyday learning, because Au revoir is best learned as a fixed expression.
If you look at it literally, it does not match natural English word-for-word order. That is normal. Many common expressions do not translate neatly word by word.
So the best approach is:
It is capitalized here only because it is at the beginning of the sentence.
Normally, in the middle of a sentence, you would write:
So the phrase itself is not normally capitalized unless sentence position requires it.
Yes, sometimes the pronunciation becomes more relaxed in fast speech.
For example, the middle sound in revoir may weaken, so it can sound a bit like:
But in writing, you still normally write the full form Au revoir.
Learners should start with the full standard pronunciation and spelling.
No. As in many French words, spelling and pronunciation do not match perfectly.
A few key points:
So you should not try to pronounce it like English spelling rules. It is better to memorize the whole sound of the phrase.