con·cen·tric 
(kən-sĕntrĭk) also con·cen·tri·cal (-trĭ-kəl)
(kən-sĕntrĭk) also con·cen·tri·cal (-trĭ-kəl)adj.
Having a common center.
[Middle English concentrik, from Medieval Latin concentricus : Latin com-, com- + Latin centrum, center; see CENTER.]
con·centri·cal·ly adv.
con′cen·trici·ty (kŏn′sĕn-trĭsĭ-tē) n.
concentric