1. an accident in which a train leaves the tracks
2. the act or process of causing something to go off course or fail
Usage: figurative

Examples

• The derailment blocked traffic for hours.
• Investigators are looking into the cause of the train derailment.
• Heavy rains caused the derailment near the bridge.
• The scandal led to the derailment of his political career.
• Budget cuts resulted in the derailment of the education reform plan.
• She worried that one mistake could cause the derailment of her project.