noun
symmetry, with reference to the interrelation of parts to form an aesthetically pleasing whole, strictly implies correspondence in the form, size, arrangement, etc. of parts on either side of a median line or plane; proportion implies a gracefulness that results from the measured fitness in size or arrangement of parts to each other or to the whole; harmony implies such agreement or proportionate arrangement of parts, as in size, color, or form, as to make a pleasing impression; balance suggests the offsetting or contrasting of parts so as to produce an aesthetic equilibrium in the whole
See symmetry in Webster's New World Roget's A-Z Thesaurus II
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