\Con*cen"tric\, Concentrical \Con*cen"tric*al\, a.
[F. concentrique. See {Concenter}.]
Having a common center, as circles of different size, one
within another.
      Concentric circles upon the surface of the water. --Sir
                                               I. Newton.
      Concentrical rings like those of an onion. --Arbuthnot.

\Con*cen"tric\, n.
That which has a common center with something else.
      Its pecular relations to its concentrics. --Coleridge.