pictograph vs syllabary

pictograph

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

  • A graphic character. 

  • A graph that represents numerical data using pictures. 

syllabary

noun
  • A writing system where each character represents a complete syllable. 

  • A table or list of syllabic letters or syllables. 

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