'symmetrical-jaw' originates from modern English as a compound of 'symmetrical' and 'jaw'; 'symmetrical' ultimately comes from Greek (through Latin/Old French), specifically the Greek elements 'sym-' (together) and 'metron' (measure), and 'jaw' originates from Old English 'ceaf' (jaw).

'symmetrical' entered English via Latin/Old French forms derived from Greek 'summetros'/'summetria'; 'jaw' developed from Old English 'ceaf' to Middle English 'jawe' and then modern English 'jaw'. The compound form 'symmetrical-jaw' is a modern descriptive formation combining these established words.

Individually, 'symmetrical' originally referred to evenness or commensurate measure; over time it extended to visual balance in features. 'Jaw' consistently referred to the lower facial bones; combined as 'symmetrical-jaw' the meaning is a straightforward descriptive fusion referring to balanced jaw shape.