symphonic

The story

1. Proto-Indo-European*ḱe?
2. Proto-Indo-European*ḱómder.?
3. Proto-Indo-European*sem-der.?
4. Proto-Hellenic*ksún
5. Ancient Greekσύν (sún)
6. Ancient Greekσῠν- (sŭn-)
7. Proto-Indo-European*bʰeh₂-
8. Proto-Hellenic*pʰōnā́
9. Ancient Greekφωνή (phōnḗ)
10. Ancient Greekσῠ́μφωνος (sŭ́mphōnos)
11. Ancient Greekσῠν- (sŭn-)
12. Ancient Greekφωνή (phōnḗ)
13. Ancient Greekσῠμφωνῐ́ᾱ (sŭmphōnĭ́ā)
14. Latinsymphōnia
15. Old Frenchsimphonie
16. Middle Englishsymphonye
17. Englishsymphony
18. English todaysymphonic

From symphony + -ic.