symmetric

adj. balanced, even, proportional, having parts corresponding to one another relative to the whole, identical on both sides

Symmetry in common usage generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically-pleasing proportionality and balance; such that it reflects beauty or perfection. The second meaning is a precise and well-defined concept of balance or "patterned self-similarity" that can be demonstrated or proved according to the rules of a formal system: by geometry, through physics or otherwise.
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Adjective
1. having similarity in size, shape, and relative position of corresponding parts
(synonym) symmetrical
(similar) bilateral, isobilateral, bilaterally symmetrical, bilaterally symmetric
(see-also) parallel

(a.)
Symmetrical.
  

<mathematics> 1. A relation y R x
If it is also antisymmetric x == y, i.e. no two different elements are related.
2. In linear algebra, a member of the tensor product of a vector space with itself one or more times, is symmetric if it is a fixed point of all of the linear isomorphisms of the tensor product generated by permutations of the ordering of the copies of the vector space as factors. It is said to be antisymmetric precisely if the action of any of these linear maps, on the given tensor, is equivalent to multiplication by the sign of the permutation in question.
(1996-09-22)