1. Something or someone that makes or investigates tunnels
   "He is a member of the engineers, a tunneller who worked on the construction of the London Underground"
   - tunneler [US]

Derived forms: tunnellers

• ballistocardiograph
• ballock
• balloon
• balloon bomb
• balloon flower
• balloon sail
• balloon seat
• balloon vine
• balloonfish
• ballooning
• balloonist
• ballot
• ballot box
• Ballota
• Ballota nigra
• balloting
• ballottement
• ballpark
• ballpen
• ballplayer
• ballpoint
• ballpoint pen
• ballroom
• ballroom dance
• ballroom dancing