(*comparative* more symmetric, *superlative* most symmetric)

- Symmetrical.
- (set theory) Of a relation
*R*on a set*S*, such that*xRy*if and only if*yRx*for all members*x*and*y*of*S*(that is, if the relation holds between any element and a second, it also holds between the second and the first).*"Is a sibling of" is a symmetric relation.*

- (cryptography) Using the same key (keys that are trivially related) for both encryption and decryption.

From Latin *symmetria* from Ancient Greek *ÏƒÏ…Î¼Î¼ÎµÏ„ÏÎ¯Î±* (summetria).