sortilege vs superstition

sortilege

noun
  • Witchcraft, magic, especially as a means of making decisions or predictions. 

superstition

noun
  • A belief or beliefs, not based on human reason or scientific knowledge, that events may be influenced by one's behaviour in some magical or mystical way. 

How often have the words sortilege and superstition occurred in a corpus of books? (source: Google Ngram Viewer )