Complex sentence: Epithalamium (Latin form of Greek ἐπιθαλάμιον "epithalamion" from ἐπί "epi" "upon," and θάλαμος "thalamos" nuptial chamber) refers to a form of poem that is written specifically for the bride on the way to her marital chamber.
Split into simpler sentences: Epithalamium (Latin form of Greek "epithalamion" from Greek; "epi -" upon, and "thalamios" nuptial chamber) specifically refers to a form of poem that is written for the bride. Or, specifically, written for the bride on the way to her marital chamber.