tun·nel·ing 
(tŭnə-lĭng)
(tŭnə-lĭng)n.
In quantum mechanics, the passing of a particle through a seemingly impenetrable barrier without a cause that is explainable by classical physics.
- dowdiness
- dowdy
- dowdyish
- dowel
- dower
- dowitcher
- do without
- Dow Jones Industrial Average
- Dow Jones Wilshire 5000
- down
- down
- down
- down-and-dirty
- down-and-out
- down and out
- down-at-heel
- down-at-the-heel
- down at the heel
- down at the heel/heels
- down at the heels
- down atthe mouth
- downbeat
- down-bow
- downbow
- downburst