dead end vs turning circle

dead end

noun
  • A street or path that goes nowhere or is blocked on one end. 

  • A position that offers no hope of progress. 

  • A split end in the hair. 

turning circle

noun
  • A place where a vehicle can turn and face in the opposite direction. 

  • The path followed by a vessel’s center of gravity when it makes a complete turn of 360° with a consistent rudder angle. (FM 55-501) 

  • The circular path formed by the wheel furthest from the centre of the turn when turning to the maximum extent. 

How often have the words dead end and turning circle occurred in a corpus of books? (source: Google Ngram Viewer )