In British English, a Juggernaut is both a literal or metaphorical force or object regarded as unstoppable, that will crush all in its path.
The term originated in India. It was a huge wagon bearing an image of the god Krishna. Especially at the town of Puri, it was drawn annually in procession in which devotees allowed themselves to be crushed under its wheels in sacrifice.
The word is altered from Jaggernaut, a title of Krishna (an incarnation of Vishnu), from the Hindi Jagannath, literally “lord of the world”.