S'empilent comes from the verb s'empiler, meaning "to pile up" or "to stack up". It's a vivid verb that evokes a sense of accumulation.
In the song, it's used to describe how memories "pile up" (Les souvenirs s'empilent), painting a picture of a summer filled with so many moments that they are stacking up in the singer's mind. This word beautifully captures the abundance and lasting impression of the summer memories.
This song is a perfect shot of nostalgia for a summer that felt like it would never end. Adèle Castillon looks back on a time with a special person and a group of friends, asking them, "L'été avec toi / Est-ce que tu t'en souviens" (The summer with you / Do you remember?). It was a time of total freedom, when they had "Le bonheur du bout des doigts" (Happiness at our fingertips) and "On se fichait de demain" (We didn't care about tomorrow).
She fills the song with super specific, personal details that make the memories feel real. We hear about being crammed on a train, late-night talks on a balcony, and even the taste of a passion fruit vape. It's a collection of small, perfect moments: a stormy yellow sky in the city of Nantes, dancing in the rain, and feeling like their group of friends was completely loyal, with "Zéro traître dans les apôtres" (Zero traitors among the apostles). The whole song feels like flipping through a box of old photos, with each line bringing back another happy memory.