Cheers
What it really means
An informal way to say "thank you". People also say it when raising a glass to drink together, and sometimes to mean "goodbye".
Context, tips & common mistakes
"Cheers" is probably the single most useful piece of British slang, and it works everywhere in the UK, across all ages and regions. Rank its meanings by frequency: thanks (most of the time), goodbye (often combined — "cheers, bye"), and the toast when glasses are raised. It is also one of the most common email sign-offs between colleagues, though you should stick to "Best wishes" or "Kind regards" when writing to someone senior you do not know. Learners most often go wrong in two ways: using it in genuinely formal situations (a visa office, a job interview), where a plain "thank you" is safer, and over-reading it — if a stranger says "cheers" after you hold a door, no reply is needed at all. Unlike in some cultures, prolonged eye contact during the drinking toast is not expected; a quick clink and "cheers" is enough.