1. long lines of vehicles moving slowly or stopped on a road due to traffic congestion
Usage: British English
2. running backs in American football who line up behind the quarterback
Usage: American football

Examples

• The accident caused massive tailbacks on the motorway.
• Drivers faced three-mile tailbacks during rush hour.
• The team’s tailbacks rushed for over 200 yards combined.
• Construction work created tailbacks stretching back to the previous junction.
• Both tailbacks are nursing injuries and may not play this weekend.
• Police warned of severe tailbacks on all major routes into the city.
• The coach rotated his tailbacks throughout the game to keep them fresh.