Mores are norms or customs. Mores derive from the established practices of a society rather than its written laws. They consist of shared understandings about the kinds of behaviour likely to evoke approval, disapproval, toleration or sanction, within particular contexts.
"Mores" are distinguished from folkways by the severity of response they invoke. While breaking a folkway is likely to turn heads of passersby, breaking a more will offend observers and possibly bring punishment. This is because mores express fundamental values of society while folkways are more nuanced customs of behavior. Taboos, for example, are the most extreme form of mores as they forbid a society's most outrageous practices, such as incest and murder. A milder example is the differences in reactions to a man and woman walking down the street topless. While the man might receive mild disapproval a woman would receive harsh sanctions for the same act.
The English word morality comes from the same root, as does the noun moral, which can mean the 'core meaning of a story'. However, mores does not, as is commonly supposed, necessarily carry connotations of morality. Rather, morality can be seen as a subset of mores, held to be of central importance in view of their content, and often formalized in some kind of moral code, e.g. commandments.
The question of how members of a society come to internalise its mores is thus of central importance to the wider question of how socialisation occurs. Most sociologists reject the thesis that formal instruction matters as much as informal social responses, for example, disgust and the ostracism of offenders. However, constant exposure to social mores is thought by some to lead to development of an individual moral core, which is pre-rational and consists of a set of inhibitions that cannot be easily characterized except as potential inhibitions against taking opportunities that the family or society does not consider desirable. These in turn cannot be easily separated from individual opinions or fears of getting caught.
Tocqueville claimed that democracy in America influenced mores properly, from a European perspective; mores became milder as conditions equalized.