• Webster's Revised Unabridged Dictionary
    • Circumferentor A graduated wheel for measuring tires; a tire circle.
    • Circumferentor 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 360°, 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.
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Century Dictionary and Cyclopedia
    • n circumferentor An instrument used by surveyors for taking angles. It consists of a graduated brass circle and an index, all of one piece, and carrying a magnetic needle suspended above the center of the circle. The index being directed to an object, the angle which it makes with the magnetic meridian is noted. The index is then directed to the second object and the angle it makes with the same meridian observed in like manner. The difference or sum (as the case may be) of the two observed angles gives the angle between the two objects. Brande and Cox. Also called circumventor and land-compass.
    • n circumferentor A device for measuring the length of the tire of a wheel, consisting of a wheel of known circumference, which is rolled over the tire.
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Chambers's Twentieth Century Dictionary
    • n Circumferentor an instrument used by surveyors and miners for measuring horizontal angles, consisting of a graduated circle, an index, and a magnetic needle suspended over the centre of a circle—now superseded by the Theodolite
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Webster's Revised Unabridged Dictionary
See Circumfer
Chambers's Twentieth Century Dictionary
L. circum, about, ferre, to carry.


In literature:

An improvement which was no doubt introduced at a very early day is the measuring wheel or circumferentor.
"The Seven Follies of Science [2nd ed.]" by John Phin