etiquette
Definitions
noun
The manners or decent behaviour to be observed in social or professional life; conventional decorum; the ceremonial code of polite society.
20 May 2018, Hadley Freeman in The Guardian, Is Meghan Markle the American the royals have needed all along? Much shock was expressed in the British press about the Palace’s utter failure to control the Markles and the Markles’ lack of etiquette.
Whenever Root would put his elbows on the table or clatter his dishes or commit any other breach of etiquette, the Professor would gently correct him.
The customary behavior of members of a profession, business, law, or sports team towards each other.
Cycling's complex etiquette contains an unwritten rule that riders in contention for a race win should not be penalised for sheer misfortune.
A label used to indicate that a letter is to be sent by airmail.