symmetrical

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Of or exhibiting symmetry.

from The Century Dictionary.

• In organic chemistry, noting compounds which contain atoms or groups at equal relative intervals in the molecule: thus, for example, chlorobenzene, which has the formula and ethylene chlorid, ClCH₂.CH₂C1, are both symmetrical compounds.
• Well-proportioned in its parts; having its parts in due proportion as to dimensions; harmonious: as, a symmetrical building; his form was very symmetrical.
• Composed of two parts whose geometrical relations to one another are those of a body and its image in a plane mirror, every element of form having a corresponding element upon the opposite side of a median or symmetral plane, upon one continued perpendicular to that plane and at the same distance from it: said also of each part relatively to the corresponding part: as, the right arm is symmetrical with the left.
• In a weakened sense, in zoology, having similar parts in reversed repetition on the two sides of a median plane, or meson, through an axis of the body, generally the longitudinal. Not all the parts need so correspond, nor need those which do correspond be equal.
• Composed of parts or determined by elements similarly related to one another, and either having no determinate order (as the three lines which by their junction form a summit of a cube) or else in regular cyclical order: said also of the parts in their mutual relation.
• Specifically, in botany, of flowers, numerically regular; having the number of members the same in all the cycles or series of organs—that is, of sepals, petals, stamens, and carpels: same as isomerous, except that in a symmetrical flower there may be more than one set of the same kind of organs. Compare regular, a., 7.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Involving or exhibiting symmetry; proportional in parts; having its parts in due proportion as to dimensions.
• adjective (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.
• adjective Having an equal number of parts in the successive circles of floral organs; -- said of flowers.
• adjective Having a likeness in the form and size of floral organs of the same kind; regular.
• adjective (Math.) Having a common measure; commensurable.
• adjective Having corresponding parts or relations.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Exhibiting symmetry; having harmonious or proportionate arrangement of parts; having corresponding parts or relations

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective exhibiting equivalence or correspondence among constituents of an entity or between different entities
• adjective having similarity in size, shape, and relative position of corresponding parts