noun

the customary code of polite behaviour in society or among members of a particular profession or group.

the rules of etiquette are changing

protocol,polite behaviour,good manners,manners,acceptable behaviour,accepted behaviour,proper behaviour,code of behaviour,rules of conduct/behaviour,decorum,form,good form,courtesy,politeness,civility,propriety,formalities,niceties,punctilios,custom,customary behaviour,convention,conformity,conventionality,politesse,the thing to do,couth