Pliegue translates to "fold" or "crease". While it might seem simple, its use in this song is quite intimate and poetic, making it stand out.
Ricardo Arjona sings, "A la medida de cada pliegue del cuerpo tuyo está hecho el mío" (My body is made to the measure of every fold of yours). This line suggests a profound connection and perfect compatibility, implying that their bodies, and perhaps their souls, are intricately designed to fit each other. It's a unique and tender way to express deep connection.
Arjona builds this one around a tailor's phrase, "a la medida" (made to measure), and turns it into the whole argument: two people who fit each other not despite their flaws but because of them. He opens by naming his own fears and frustrations before she even appears, then places her arrival at night in "Con blusa blanca y traje oscuro" (a white blouse and a dark suit), as if the two of them were already dressed for a fitting.
The clearest line is "Como dos aguas del mismo rio" (like two waters of the same river), and everything else builds toward it: "Tú tienes alas que vuelan poco" (you have wings that barely fly) against his dreams that never land, her secrets kept in "Es mi silencio pa' conservarlos" (my silence, to guard them), his own past folded into her present so he can finally forget it. It plays as a love song about fit as a kind of craft rather than luck, someone cut exactly to another person's shape.