SUPERSTITION

Superstition is any belief or practice that is considered irrational  or supernatural  example  if it arises from ignorance, a misunderstanding of science or causality, a positive belief in fate or magic, or fear of that which is unknown.

 It is commonly applied to beliefs and practices surrounding luck, prophecy, and certain spiritual beings, particularly the belief that future events can be foretold by specific (apparently) unrelated prior events. 

word superstition is often used to refer to a religion not practiced by the majority of a given society regardless of whether the prevailing religion contains alleged superstitions.

Identifying something as superstition is generally pejorative. Items referred to as such in common parlance are commonly referred to as folk belief in folkloristics.