familiar : Idioms & Phrases

• noun a spirit (usually in animal form) that acts as an assistant to a witch or wizard
  familiar.
  

WordNet

• a demon or evil spirit supposed to attend at call.

Webster 1913

• adjective satellite frequently experienced; known closely or intimately
  well-known.
  
  • a long-familiar face
  • a well-known voice reached her ears

WordNet