Symmetry
mid 16th century (denoting proportion): from French symétrie or Latin symmetria, from Greek, from sun- ‘with’ + metron ‘measure’.
wiktionary
From Latin symmetria, from Ancient Greek συμμετρία(summetría), from σύμμετρος(súmmetros, “symmetrical”), from σύν(sún, “with”) + μέτρον(métron, “measure”). Synchronically, syn- + -metry.
etymonline
symmetry (n.)
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.