Arcobaleno literally translates to "rainbow". It's a beautiful and evocative word that paints a vivid image.
In the song, it's used metaphorically in the line "Questo grande arcobaleno non può sciogliere un veleno" (This great rainbow cannot dissolve a poison). This suggests that even something as beautiful and hopeful as a rainbow cannot overcome the deep-seated pain or 'poison' in the relationship, making it a poignant and memorable choice.
This duet is a conversation between two people whose relationship is ending, and it's incredibly dramatic! They know it's over, but they just can't seem to let go. They describe their love as a poison they have to drink together, saying even a "grande arcobaleno" (big rainbow) can't fix things. It's a powerful way to say that even the beautiful memories can't heal the damage.
The whole song is this back-and-forth of pain and desperation. They agree that they can't erase their "grande amore" (great love), but they're stuck. The chorus is the heart of the problem: "Un cuore malato fa male perché / Batte forte soltanto per te" (A sick heart hurts because / It beats strongly only for you). They feel like they are physically ill with love for each other, even when they know "una speranza non c'è" (there is no hope). It gets even more intense when one says "Io posso morire" (I can die) and the other begs them not to say it. It's a perfect song for when you want to feel all the feelings about a love that's impossible to leave behind.
Lara Fabian was born in Etterbeek, Belgium, in 1970, to a Belgian father and a Sicilian mother, and started singing lessons before she'd really learned to talk. She trained for ten years at the Brussels Royal Conservatory of Music, piano and composition included, and was already working the Brussels club circuit as a teenager. A fourth-place finish at the 1988 Eurovision Song Contest with "Croire" got her noticed at home, but it was a move to Quebec in 1991 that changed the trajectory of her career: her French-language records found a much bigger audience across the Atlantic than they had in Belgium.
Carpe Diem went triple platinum in 1994 and 1997's Pure carried the hit "Je t'aime." By 1999 she'd crossed into English with a self-titled album built around "Adagio" and the dance-pop hit "I Will Love Again." She still records in French, English and Italian, drawing on her mother's language for songs like this one, and she remains the best-selling Belgian-born female artist of all time.