circumferentor \circum`feren"tor\, n. see circumfer.
   1913 webster
   1. a surveying instrument, for taking horizontal angles and
      bearings; a surveyor's compass. it consists of a compass
      whose needle plays over a circle graduated to 360deg,
      and of a horizontal brass bar at the ends of which are
      standards with narrow slits for sighting, supported on a
      tripod by a ball and socket joint.
      1913 webster

   2. a graduated wheel for measuring tires; a tire circle.
      1913 webster
see also:
circumfer