'symmetrical-legged' is a compound of the adjective 'symmetrical' and the adjective-forming past-participial suffix attached to 'leg' ('legged'), where 'symmetrical' originates ultimately from Greek and 'leg' from Old English.

'symmetrical' originates via Latin and French from Greek 'summetria' (συμμετρία), while 'leg' comes from Old English 'leg'; the compound 'symmetrical-legged' is a modern English formation combining these components.

Initially, 'symmetrical' meant 'having measured proportion' and 'legged' signified 'having legs'; combined in modern usage they mean 'having legs that are symmetrical' (the component meanings remain largely intact).