The story
- Proto-Indo-European*speḱ-
- Proto-Indo-European*spéḱyeti
- Proto-Italic*spekjō
- Latinspeciō
- Latinspectrum
- Englishspectrum
- Englishspectro-
- Proto-Indo-European*spéḱyeti
- Proto-Hellenic*sképt͏̌omai
- Ancient Greekσκέπτομαι (sképtomai)
- Ancient Greekσκοπός (skopós)
- Ancient Greekσκοπέω (skopéō)
- Latinspectrum
- Frenchspectro-
- Ancient Greekσκοπέω (skopéō)
- Frenchspectroscopie
- Frenchspectroscopique
- English todayspectroscopic
From spectro- + -scopic, or borrowed from French spectroscopique.
Etymology from Wiktionary, CC BY-SA 4.0.