spectrofluorescence

The story

1. Proto-Indo-European*speḱ-
2. Proto-Indo-European*spéḱyeti
3. Proto-Italic*spekjō
4. Latinspeciō
5. Latinspectrum
6. Englishspectrum
7. Englishspectro-
8. Proto-Indo-European*bʰel-
9. Proto-Indo-European*bʰlewH-
10. Proto-Indo-European*bʰluH-yé-ti?
11. Latinfluō
12. Latinfluor
13. Englishfluor
14. Englishfluorite
15. Middle Low Germanspar
16. Old Englishspærstān
17. Middle Englishsparston
18. Englishsparstonebf.
19. Englishspar
20. Englishfluorspar
21. Englishfluorescence
22. English todayspectrofluorescence

From spectro- + fluorescence.