1. a road or path that goes under another road or a railway

Examples

• The pedestrian underpass connects both sides of the busy highway.
• We drove through the underpass to avoid the traffic light above.
• The new underpass will allow trains to pass over the road safely.
• Children use the underpass to walk to school without crossing the street.
• The underpass was flooded after the heavy rain last night.
• Construction of the underpass took six months to complete.