gradate vs sync

gradate

verb
  • To change imperceptibly from one gradation of tone etc. to another. 

  • To arrange in order of grades. 

  • To bring to a certain strength or grade of concentration. 

sync

verb
  • To synchronize, especially in the senses of data synchronization, time synchronization, or synchronizing music with video. 

  • To flush all pending I/O operations to disk. 

noun
  • A music synchronization license, allowing the music to be synchronized with visual media such as films. 

  • Harmony. 

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