su ‧ per ‧ sti ‧ tion /ˌsuːpəˈstɪʃ ə n $ -pər-/ BrE AmE noun [uncountable and countable]
[ Date: 1400-1500 ; Language: Old French ; Origin: Latin superstitio , from superstes 'standing over someone' , from stare 'to stand' ]
a belief that some objects or actions are lucky or unlucky, or that they cause events to happen, based on old ideas of magic:
the old superstition that walking under a ladder is unlucky