|Origin:||Perhaps copying the action|
jam2 past tense and past participle jammed, present participle jamming
to push something somewhere using a lot of force, until it can move no further:
push hard[transitive always + adverb/preposition]
He jammed his foot on the accelerator and the car sped off.
A chair had been jammed up against the door.
if a moving part of something jams, or if you jam it, it no longer works properly because something is preventing it from moving:
machine[intransitive and transitive] also jam up
The front roller has jammed on the photocopier.
if a lot of people or vehicles jam a place, they fill it so that it is difficult to move [= cram]:
block[intransitive and transitive] also jam up
Crowds jammed the entrance to the stadium.
jam into➔ jammed (2)
They all jammed into the car.
to play music in an informal way with other people ➔ jam session
music[intransitive] also jam outAPM
to slow down a car suddenly by putting your foot down hard on the brake
if telephone calls jam the switchboard of an organization, so many people are phoning the organization that it cannot deal with them all:
Viewers jammed the switchboard with complaints.
to deliberately prevent broadcasts or other electronic signals from being received, by broadcasting signals on the same wavelength
8 American English spoken
used to say that someone is doing something very quickly or well