1. the process or activity of digging tunnels
2. a phenomenon in quantum physics where particles pass through energy barriers
Usage: physics

1. present participle of tunnel; digging or making a tunnel

Examples

• The tunnelling project under the river will take three years to complete.
• Workers are tunnelling through solid rock to build the subway line.
• The company specializes in tunnelling for underground utilities.
• Quantum tunnelling allows electrons to pass through barriers they shouldn’t classically be able to cross.
• The miners have been tunnelling for months to reach the coal deposits.
• Modern tunnelling techniques have made underground construction much safer.
• The tunnelling operation requires specialized equipment and expertise.