Having a common center, such that two or more spheres, circles, or segments of circles are within one another.
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con·cen·tric kən-'sen-trik, (')kän- adj having a common center <\concentric circles>
con·cen·tri·cal·ly -tri-k(ə-)lē adv
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con·cen·tric (kən-senґtrik) [L. concentricus, from con- together + centrum center] having a common center; extending out equally in all directions from a common center.Medical dictionary. 2011.