SUPERSTITION

[noun] - (a) belief which is not based on human reason or scientific knowledge, but is connected with old ideas about magic etc.According to superstition, if you walk under a ladder it brings you bad luck. [U]Out of superstition, she never has 13 people sitting at the table to eat together. [U]I don't believe that four-leaved clovers are lucky - that's just a superstition. [C]Even in modern times, people cling to superstitions handed down through the centuries. [C]There's a superstition that if you break a mirror, you'll have seven years' bad luck. [C + that clause]