The description of etiquette from the english dictionary says -
"conventional requirements as to social behaviour; proprieties of conduct as established in any class or community or for any occasion."
This basically means, that it is the expected standard of behaviour for a certain event or environment.
For example, at a Football (Soccor) match you are expected to cheer your team to encourage their success, singing and shouting from the start of the match.
- Say hello when you see someone
- Use the outside cutlery first, and work your way in with each meal at a formal meal
- Don't talk with your mouth full
- Bow when you enter a Dojo