magnetoplasmadynamic

The story

1. Ancient GreekΜάγνης (Mágnēs)
2. Ancient Greekμᾰ́γνης (mắgnēs)
3. Old Frenchmagnete
4. Ancient Greekμᾰ́γνης (mắgnēs)
5. Latinmagnēs
6. Middle Englishmagnete
7. Englishmagnet
8. Englishmagnet-
9. Englishmagneto-
10. Proto-Hellenic*plátʰyō
11. Proto-Hellenic*plát͏̌t͏̌ō?
12. Ancient Greekπλάσσω (plássō)
13. Ancient Greekπλᾰ́σμᾰ (plắsmă)
14. Late Latinplasma
15. Englishplasma
16. Proto-Indo-European*dewh₂-
17. Proto-Hellenic*dunamai
18. Ancient Greekδῠ́νᾰμαι (dŭ́nămai)
19. Ancient Greekδύναμις (dúnamis)
20. Ancient Greekδυναμικός (dunamikós)
21. Frenchdynamique
22. Englishdynamic
23. Englishplasmadynamic
24. English todaymagnetoplasmadynamic

From magneto- + plasmadynamic.