Cucú is the Spanish onomatopoeia for the sound a cuckoo clock makes, and it's also the name of the bird itself. It's a charming and somewhat whimsical word that immediately brings to mind the imagery of a cuckoo clock.
In this song, the
"El Reloj Cucú" frames a father's death through a child's bedtime ritual. It opens on an ordinary night: "El relojito cucu sonaba" ("The little cuckoo clock was chiming"), a goodnight kiss, the light switched off. Once the room goes dark, the cuckoo becomes who the child talks to: "Oye cucú, papá se fue" ("Listen cuckoo, Dad left"), "Prende la luz, que tengo miedo" ("Turn on the light, because I'm scared").
The middle verses turn to the mother who carried the loss alone, who "aguantó todito" ("endured everything") and "lloraba en silencio" ("cried in silence") raising the kids by herself. The closing verses widen out to the whole family — siblings who "crecimos juntos" ("grew up together") still missing him years later — and end on grief with no reply: "Le pregunto tanto, tanto no contesta nada" ("I ask him so much, so much, he answers nothing"), the clock's ticking standing in for the time that keeps moving without him.