> 4. US English really needs to re-acquaint (no pun intend) itself with the word "acquaintance" as an alternative to "friend". The almost universal use of "friend" to describe anyone you know (even from the most singular and minor of interactions) really robs verbal behavior about the social environment here of so much subtlety
Well, we just call them brothers or sisters if they are that close. Actually…
You can see the same thing with "neighbor". In the UK that refers to someone who lives in one of the houses adjacent to yours. In the USA it can refer to anyone who lives anywhere in some loosely-defined neighborhood. "My neighbor" can be someone who lives a mile or two away, which by UK standards is absurd.
Well, we just call them brothers or sisters if they are that close. Actually…