To Tunnel

1. (transitive) To make a tunnel through or under something; to burrow.
2. (intransitive) To dig a tunnel.
3. (computing, networking) To transmit something through a tunnel (wrapper for insecure or unsupported protocol).
4. (transitive, medicine) To insert a catheter into a vein to allow long-term use.
5. (physics) To undergo the quantum-mechanical phenomenon where a particle penetrates through a barrier that it classically cannot surmount.