concentrator

[Eng. concent rat(e); -or.] 1. Ord. Lang.: One who or that which concen trates. 2. Min .: An apparatus for the separation of dry, comminuted ore, according to the gravity of its particles, by exposing a falling sheet of ore-dust to intermittent puffs of air. căn-çěn-tric, còn-çěn-tric-al, *con-çen'trick, a. [Eng. concentr (e); -ic, -ical.] 1. Geom.: Having the same center. A geometric term used specially of circles. "The manner of its concretion is by concentrical rings, like those of an onion about the first kernel."-Arbuthnot, On Diet. *2. Fig . ( of persons): Having the same centers of thought or affection. "If, as in water stirr'd, more circles be Produc'd by one, love such additions take; Those, like so many spheres, but one heav'n make; For they are all concent rick unto thee."-Donne. concentric circles, s. pl . Circles having the same center, but, of course, different lengths of diameter and radii.