knock on

transitive verb

Definition of knock on

(Entry 1 of 3)

: to knock onward : knock forward specifically : to knock (the ball in rugby) forward in the direction of the opponents' dead-ball line with the hand or arm

knock-on

noun

plural knock-ons

Definition of knock-on (Entry 2 of 3)

: the action of knocking on

knock-on

adjective

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Definition of knock-on (Entry 3 of 3)

: 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