I am pretty sure I am aware of the meaning of "Mr.", which is a title used before the family name or full name in of a man who has no other title, or when talking to man who holds a particular official position.
source: Cambridge Dictionary
However, the usage of "Mr." or "Mr" confuses me a bit, that is whether the suffix dot "." in "Mr." is optional or required.
I see both two forms are commonly used, Google Ngram shows that the former is more commonly used than the latter.
even Cambridge Dictionary uses both of them.
Good afternoon, Mr Dawson.
I’m afraid I can’t agree with what’s just been said, Mr. Chairman
Is it a matter of AmE vs. BrE or just something about style?