trolleybus

The story

1. Proto-Germanic*truzlōną
2. Middle High Germantrollen
3. Old Frenchtroller
4. Middle Englishtrollen
5. Englishtroll
6. Englishtrolley
7. Proto-Indo-European*h₃ep-
8. Proto-Italic*opnis
9. Latinomnis
10. Latinomnibu
11. Frenchomnibus
12. Englishomnibusclip.
13. Englishbus
14. English todaytrolleybus

From trolley + bus.