Numbers commensurable in power

Commensurable \Com*men"su*ra*ble\, a. [L. commensurabilis; pref.
   com- + mensurable. See {Commensurate}, and cf.
   {Commeasurable}.]
   Having a common measure; capable of being exactly measured by
   the same number, quantity, or measure. --
   {Com*men"su*ra*ble*ness}, n.
   [1913 Webster]

   {Commensurable numbers} or {Commensurable quantities}
      (Math.), those that can be exactly expressed by some
      common unit; thus a foot and yard are commensurable, since
      both can be expressed in terms of an inch, one being 12
      inches, the other 36 inches.

   {Numbers commensurable in power}, or {Quantities
   commensurable in power}, those whose squares are
      commensurable.
      [1913 Webster]