The story
- Proto-Indo-European*h₁ep-
- Proto-Indo-European*h₁éps
- Proto-Indo-European*h₁épi
- Proto-Hellenic*epí
- Ancient Greekἐπί (epí)
- Ancient Greekἐπῐ- (epĭ-)
- Ancient Greekθάλαμος (thálamos)
- Ancient Greekἐπιθαλάμιος (epithalámios)
- Ancient Greekἐπιθαλάμιον (epithalámion)
- Latinepithalamium
- English todayepithalamium
Learned borrowing from Latin epithalamium, itself borrowed from Ancient Greek ἐπιθαλάμιον (epithalámion, “bridal song”), neuter form of ἐπιθαλάμιος (epithalámios), from ἐπί (epí, “upon”) + θάλαμος (thálamos, “inner chamber, wedding chamber”).
Etymology from Wiktionary, CC BY-SA 4.0.