amulet vs icon

amulet

noun
  • A kind of protective charm or ornament, often bearing magical symbols, worn for protection against ill will, negative influences, or evil spirits. 

icon

noun
  • An image, symbol, picture, or other representation usually as an object of religious devotion. 

  • A small picture that represents something. 

  • A person or thing that is the best example of a certain profession or some doing. 

  • A type of religious painting portraying a saint or scene from Scripture, often done on wooden panels. 

  • A word, character, or sign whose form reflects and is determined by the referent; onomatopoeic words are necessarily all icons. 

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