what is a pub meant for?
A pub is basically a licensed establishment that sells alcoholic drinks, like beer. Not my thing, but we have a lot of them in my city.
when did the word first appear in history?
I'm not sure when the word itself first appeared, but pubs have been around in some form or another since ancient Roman times!
is this allowed in all countries?
Well, there are a lot of middle eastern countries where alcohol isn't allowed. If I was looking for a pub, I would stick to Britain, Ireland, Canada, Australia, etc.