asymmetry n.

prefix meaning "not, without," from Greek a-, an- "not" (the "alpha privative"), from PIE root *ne- "not" (source also of English un-).

In words from Greek, such as abysmal, adamant, amethyst; also partly nativized as a prefix of negation (asexual, amoral, agnostic). The ancient alpha privatum, denoting want or absence.

Greek also had an alpha copulativum, a- or ha-, expressing union or likeness, which is the a- expressing "together" in acolyte, acoustic, Adelphi, etc. It is from PIE root *sem- (1) "one; as one, together with."

1560s, "relation of parts, proportion," from French symmétrie (16c.) and directly from Latin symmetria, from Greek symmetria "agreement in dimensions, due proportion, arrangement," from symmetros "having a common measure, even, proportionate," from assimilated form of syn- "together" (see syn-) + metron "measure" (from PIE root *me- (2) "to measure"). Meaning "harmonic arrangement of parts" first recorded 1590s.

"destitute of symmetry, unsymmetrical," 1680s; see asymmetry + -ical. Other forms that have served as an adjective based on asymmetry are asymmetral (1620s), asymmetrous (1660s), and asymmetric (1839); only the last seems to have any general currency. Related: Asymmetrically.