CANCERBERO Definición y sinónimos de cancerbero en el Cerbero is a mythical creature in Greek mythology. Its portrayal often shows it as a multi-headed canine protecting the gates of Hades. In some myths, Cancerbero possesses three heads, while in others it can have a maximum of nine separate heads. The term "cancerbero" is additionally used to refer to a watchful and unyielding guardian.