Vladimir Berkov said:The interesting thing is that today pretty much anything involving a suit-style coat, tie and no jeans is a "suit." Blazers, sportcoats, actual suits are all sort of lumped together. Any formal-ish colored coat, tie and trousers combination that is not a business suit and is worn for a wedding or other special occasion is a "tux."
The "tux" thing (It winds me up the wrong way when people call tails a tux!) is mostly a US thing, I think. I've never known anyone in the UK (or Sweden since I moved here) refer to non-black tie as a "tux", although the term "tux" is something I've rarely heard in real life, except on TV.