From Greek 'tonos' (stretching, pitch), via Latin 'tonus' — sound was conceived as the vibration of something stretched taut.
A musical or vocal sound; the general character of something.
From Old French 'ton,' from Latin 'tonus' meaning 'a sound, tone, accent,' from Greek 'tonos' meaning 'vocal pitch, accent, stretching, tension,' from 'teinein' (to stretch). Sound was conceived as stretched, taut vibration. Key roots: teinein (Greek: "to stretch").