symmetry (n.)
1560s, "relation of parts, proportion," from Middle 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 "meter" (see meter (n.2)). Meaning "harmonic arrangement of parts" first recorded 1590s.