initiate vs specialist

initiate

noun
  • One who is oriented in and familiar with a topic or subject; especially, one who is an expert in it. 

  • A new member of an organization. 

  • One who has been through a ceremony of initiation. 

verb
  • To instruct in the rudiments or principles; to introduce. 

  • To do the first act; to perform the first rite; to take the initiative. 

  • To confer membership on; especially, to admit to a secret order with mysterious rites or ceremonies. 

  • To begin; to start. 

specialist

noun
  • Someone who is an expert in, or devoted to, some specific branch of study or research. 

  • A stenotopic species. 

  • A physician whose practice is limited to a particular branch of medicine or surgery. 

  • Any of several non-commissioned ranks corresponding to that of corporal. 

  • An organism that is specialized for a particular environment. 

adj
  • Specialised, involving detailed knowledge of a restricted topic. 

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