Definition of: symmetry

(sim′ə·trē) noun plural ·tries
1. Corresponding arrangement or balancing of the parts or elements of a whole in respect to size, shape, and position on opposite sides of an axis or center; hence, loosely, congruity; harmony; also, an instance of such arrangement.
2. The element of beauty in nature or art that results from such arrangement and balancing.
3. Biol. Regular arrangement of parts or organs in an animal body so that a division will give halves corresponding in shape, size, function, relative position, etc.; similarity of structure.
4. Bot. Equality of number in the whorls of a flower, as of sepals, petals, etc.
5. Math. An arrangement of pairs of points in a general system such that the set of lines joining them together is divided into equal parts by a line, a plane, or a point.
6. Mineral. The symmetrical distribution of non–parallel but equivalent directions (faces, edges, etc.) in a crystal with reference to certain planes or lines called planes or axes of symmetry. [<MF symmetrie <LL symmetria <Gk. <symmetros measured together <syn- together + metron a measure] Synonyms: agreement, conformity, harmony, order, parity, proportion, regularity, shapeliness. See HARMONY. Antonyms: deformity, discordance, disproportion, shapelessness.