\Sym*met"ric*al\, a. [Cf. F. sym['e]trique. See
{Symmetry}.]
1. Involving or exhibiting symmetry; proportional in parts;
   having its parts in due proportion as to dimensions; as, a
   symmetrical body or building.
2. (Biol.) Having the organs or parts of one side
   corresponding with those of the other; having the parts in
   two or more series of organs the same in number;
   exhibiting a symmetry. See {Symmetry}, 2.
3. (Bot.)
   (a) Having an equal number of parts in the successive
       circles of floral organs; -- said of flowers.
   (b) Having a likeness in the form and size of floral
       organs of the same kind; regular.
4. (Math.) Having a common measure; commensurable.
   (b) Having corresponding parts or relations.
Note: A curve or a plane figure is symmetrical with respect
      to a given line, and a line, surface, or solid with
      respect to a plane, when for each point on one side of
      the line or plane there is a corresponding point on the
      other side, so situated that the line joining the two
      corresponding points is perpendicular to the line or
      plane and is bisected by it. Two solids are symmetrical
      when they are so situated with respect to an
      intervening plane that the several points of their
      surfaces thus correspond to each other in position and
      distance. In analysis, an expression is symmetrical
      with respect to several letters when any two of them
      may change places without affecting the expression; as,
      the expression a^{2}b + ab^{2} + a^{2}c + ac^{2} +
      b^{2}c + bc^{2}, is symmetrical with respect to the
      letters a, b, c. -- {Sym*met"ric*al*ly}, adv. --
      {Sym*met"ric*al*ness}, n.