et·i·quette 
/ˈɛtɪkət/ noun
/ˈɛtɪkət/ noun [noncount] : the rules indicating the proper and polite way to behave
▪ Her failure to respond to the invitation was a serious breach of etiquette. ▪ a book of etiquette ▪ telephone etiquette [=the proper way to behave when speaking on the telephone]
▪ Her failure to respond to the invitation was a serious breach of etiquette. ▪ a book of etiquette ▪ telephone etiquette [=the proper way to behave when speaking on the telephone]
