nanometer

The story

1. Ancient Greekνᾶνος (nânos)
2. Latinnānus
3. Englishnano-
4. Proto-Indo-European*med-
5. Proto-Indo-European*médeti
6. Proto-Germanic*metaną
7. Proto-West Germanic*metan
8. Old Englishmetan
9. Middle Englishmeten
10. Middle Englishmetere
11. Englishmeter
12. English todaynanometer

From nano- + meter.