Concavidades translates to "concavities" or "hollows". It's a rather uncommon and evocative word to find in song lyrics, making it stand out.
In "Triángulo", iLe uses this word to describe the inner, hidden spaces within herself where emotions and experiences reside. She sings about a "triángulo en el espacio abierto de mis concavidades" (a triangle in the open space of my concavities), creating a poetic and somewhat mysterious image of her internal world. This unique usage invites listeners to ponder the deeper meanings of her introspection.
iLe turns her own body into a geometry problem. Every verse opens with a hesitant self-correction — "Tengo un triángulo perdón" ("I have a triangle... sorry") — then restates the same image as something happening TO her rather than something she owns: "Hay un triángulo" ("There's a triangle"). Threads knot her fingers, oaks stretch around her, a hole empties her out, verse by verse, in the flat vocabulary of a diagram instead of a feeling. It closes on "Que me desgarro toda, hasta que soy sin ti" ("that tears me apart completely, until I'm without you") — the shapes were never abstract; they were the shape of losing someone.