or symmetrical, adj. 1. (of a figure or configuration) identical with its own reflection in an axis of symmetry or center of symmetry; having pairs of points identically placed, except for sense, with respect to some line, point, plane, etc. 2.(of a relation) holding between a pair of arguments x andy when and only when it also holds between yand x. For example, ... is a sibling of... is symmetrical, since one must be one's brother's or sister's brother or sister; but... is a brother of... is not symmetrical, since a female is not the brother of her brother. Compare asymmetric, antisymmetric, non-symmetric. See also equivalence relation.
3a. (of a function, f, with respect to a point,c) such that for all x
f(c + x) = f(c - x).
b. in particular, if c is the origin, even. 4. (of a binary operator) having the property that the order of arguments is immaterial; commutative. 5. (of a tensor) such that its components satisfy either T^ab = T^ba or T_ab = T_ba.