Marfil translates to "ivory." It's a less common word in everyday Spanish, making it stand out in lyrics.
In the song, it's used to describe the color of someone's eyes: "De tus ojos de marfil" (Of your ivory eyes). This evokes a sense of delicate beauty and perhaps a pale, striking color, adding a poetic touch to the description.
This song feels like a journey through a cold, introspective winter. The singer is surrounded by the quiet of a world where "Todos se han marchado de aquí" [Everyone has left here] and "Solo el invierno quedó" [Only winter remained]. There's a sense of longing and perhaps a bit of stubborn hope, as he notes the snow is the color of his beloved's "ojos de marfil" [ivory eyes]. He hasn't written a letter because, as he says, "Lo estoy diciendo" [I'm saying it now] through the song itself.
Even though the land is "fría y gris" [cold and gray], he believes "ya irá floreciendo" [it will bloom]. He knows that "para ser feliz / Hay que intentar parecerlo" [to be happy / You have to try to seem so]. There's a beautiful, almost defiant spirit here, especially when he talks about facing the coming storm and the breaking waves, which are "Solo tratan de decir / Que están muriendo" [Only trying to say / That they are dying]. But despite the melancholy, he's determined to keep going, to "morir cantando / Como dices tú" [die singing / As you say]. He describes himself as "un tipo extraordinario / De lo más común" [an extraordinary guy / Of the most common kind], which is such a wonderfully humble and relatable line, don't you think?