Equivocado means "mistaken" or "wrong." It's a key word in the song's title, "Regalo Equivocado" (Mistaken Gift), and central to the narrative.
The singer receives a Christmas gift that was clearly intended for someone else—his partner's secret lover. This word perfectly encapsulates the painful realization that the gift, and perhaps the relationship itself, was a mistake, making it both memorable and emotionally resonant.
"Regalo Equivocado" ("Wrong Gift") tells the story of a man sitting by the Christmas tree, opening a present from his ex. Instead of a sweet surprise, he finds the name of her new lover written on the perfumed envelope inside, a gift meant for someone else that got sent to him by mistake.
The mix-up makes it painfully clear she has already moved on. He wipes his own name off the package and mails it back to her, admitting he will never again share a Christmas kiss with her, or the traditional twelve grapes at midnight on New Year's Eve, now that she saves those moments for someone new.
It is a heartbreak song dressed up as a Christmas story, using a wrapped gift to say what the singer cannot say directly: that the relationship is over, and he found out in the worst possible way.