Arquitectura literally means "architecture". It's an interesting word choice because it's not commonly used in reggaeton lyrics, making it stand out.
In the song, Brytiago uses it metaphorically to describe a woman's figure, specifically her waist: "Esa cintura es una arquitectura" (That waist is an architecture). This comparison elevates her physique to a work of art, implying it's perfectly sculpted and impressive, much like a well-designed building.
In "La Baby," Brytiago paints a picture of a passionate and secret romance. The connection between him and his partner is all about letting things happen naturally, or as he says, "Te gusta que fluya, que no se force" (You like it to flow, that it's not forced). Their relationship is an "open secret" ("un secreto a voces"), known to some but not officially public. The mood is set with expensive whiskey, like Macallan 18, as they move from a car to the bedroom, showing a spontaneous and intense attraction.
Brytiago uses the metaphor of making a movie to describe their intimacy. He says, "hicimos una peli y la baby ni siquiera actĂșa" (we made a movie and the baby doesn't even act), suggesting their connection is raw and authentic. He admires her intensely, calling her waist "an architecture" ("una arquitectura") and his queen. The song is a celebration of a powerful, discreet, and fiery connection with a woman he finds captivating.