hieroglyph vs pictogram

hieroglyph

noun
  • An element of an ideographic (hieroglyphic) writing system. 

  • Any obscure or baffling symbol. 

verb
  • To represent by hieroglyphs. 

pictogram

noun
  • A picture that represents a word or an idea by illustration. 

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