The difference between "tunneling" and "tunnelling" lies in their spelling and origin.
- Tunneling is the American English spelling.
- Tunnelling is the British English spelling.
Both spellings refer to the same action: the process of creating a tunnel.
Examples:
- Tunneling: "The construction crew is tunneling through the mountain to build a new road."
- Tunnelling: "The engineers are using advanced techniques for tunnelling under the river."
The choice of spelling depends on the context and the audience. In American English, "tunneling" is the preferred spelling, while in British English, "tunnelling" is preferred.
