1. Something; such as, a belief or institution, which elicits blind and destructive devotion or to which people are ruthlessly sacrificed: Athena's parents were concerned about the juggernaut to which their daughter was devoted.

The fleet of trucks advanced on the pit mine like a juggernaut, inexorably powerful and unstoppable.

When capitalized, Juggernaut refers to the idol of the Hindu god Krishna, which was pulled around on a huge cart or wagon.

2. Origin: The Hindustani name for juggernaut was jaganath, "world-protector".

Devotees of the god are said to have thrown themselves under the wheels to be crushed to death in their frenzies of devotion; so, juggernaut came to mean anything to which we are blindly enslaved or as an irresistible crushing force.

Whether this was actually the practice or merely a misinterpretation of the deaths of those caught in the crush of people pulling the over-sized wagon, the British associated willful self-destruction with the Jagannath during the festival of Puri every year.