etiquette, name for the codes of rules governing social or diplomatic intercourse. These codes vary from the more or less flexible laws of social usage (differing according to local customs or taboos) to the rigid conventions of court and military circles, and they extend to the legal, medical, and other professions. All cultures include forms of etiquette; often, etiquette has been used to enforce class distinctions, as well as safeguarding against conflict in social interactions.