advanced vs ahead

advanced

adj
  • with greater complexity, more difficult 

  • At or close to the state of the art. 

  • Pronounced farther to the front of the vocal tract. 

  • Indicating a time ahead of the correct time. 

  • Having moved forward in time or space (e.g. advanced ignition timing). 

  • In a late stage of development; greatly developed beyond an initial stage. 

ahead

adv
  • To a later time. 

  • At an earlier time; beforehand; in advance. 

  • To an earlier time. 

  • In or for the future. 

  • At or towards the front; in the direction one is facing or moving. 

  • So as to be further advanced, either spatially or in an abstract sense. 

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