social convention

A convention is a set of agreed, stipulated or generally accepted social norms, norms, standards or criteria, often taking the form of a custom.Certain types of rules or customs may become law, and regulatory legislation may be introduced to formalise or enforce the convention (e.g. laws which determine which side of the road vehicles must be driven). In a social context, a convention may retain the character of an "unwritten" law of custom (e.g. the manner in which people greet each other, such as by shaking each other's hands).
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Synonyms and related words:
bon ton, conformity, consuetude, convention, custom, established way, etiquette, fashion, folkway, manner, manners, mores, observance, practice, praxis, prescription, proper thing, ritual, standard behavior, standard usage, standing custom, time-honored practice, tradition, usage, use, way, what is done, wont, wonting