Meaning of TUNNELING in English
or barrier penetration
In physics, the passage of a particle through a seemingly impassable energy barrier.
Though a particle's energy may be too low to surmount a barrier in classical physics, the particle may still cross the barrier as a consequence of its quantum-mechanical wave properties. An important application of this phenomenon is in the operation of the scanning tunneling microscope.
Britannica Concise Encyclopedia. Краткая энциклопедия Британика. 2012