electrodynamical

The story

1. Frenchélectro-
2. Ancient Greekἤλεκτρον (ḗlektron)
3. Latinēlectrum
4. Latinelectro-
5. Englishelectro-
6. Proto-Indo-European*dewh₂-
7. Proto-Hellenic*dunamai
8. Ancient Greekδῠ́νᾰμαι (dŭ́nămai)
9. Ancient Greekδύναμις (dúnamis)
10. Ancient Greekδυναμικός (dunamikós)
11. Frenchdynamique
12. Englishdynamic
13. Proto-Indo-European*h₂el-
14. Proto-Indo-European*h₂élisder.?
15. Englishdynamical
16. English todayelectrodynamical

From electro- + dynamical.