Supertitions and folklore

Supertitions are a belief or notion, not based on reason or knowledge. The word is often used pejoratively to refer to supposedly irrational belief of others, and its precise meaning is therefore subjective. It is commoly appalied to beliefs and practices surrounding luck, prophecy and spiritual beings.
In the academic discipline of folkloristiesthe term "supertitions" is used to denote any general, culturally variable beliefs in  supernatural "reality". Depending on a given culture's belief set, its supertitions may relate to things that are not fully understood or understood at all, such as cemeteries, animals, demons, a devil, deceased ancestors, the weather, ripping one's sock, gambling, sports, food, holidays, occupations, excesive scrupulosity, death, luck, and spirits. Urban legens are also sometimes classed as supertition, especially if the moral of the legend is to justify fears about socially alien people or conditions. In Western folklore, supertitions associated with bad luck include Friday the 13th and walking under a ladder. In India, there is a supertition that a pregnant woman should avoid going outside during an eclipse in order to prevent her baby being born with a facial birthmark. In Korea, there is a supertition that leacing a fan on in a closed room will suffocate the occupants.