I. ˈ ̷ ̷ˌ ̷ ̷ noun
( plural knock-ons )
Etymology: knock on
: the action of knocking on
II. adjective
Etymology: knock on
: produced or projected as a result of the collision of an energetic particle (as a neutron or fission fragment) from outside an atom with an elementary particle inside
a knock-on shower of particles
a knock-on atom
a knock-on electron