There are 2 main definitions of jam in English:

jam1

Line breaks: jam
Pronunciation: /dʒam
 
/

verb (jams, jamming, jammed)

1 [with object and adverbial] Squeeze or pack tightly into a specified space: four of us were jammed in one compartment people jammed their belongings into cars [no object, with adverbial]: mum, dad, and I jammed into the pickup truck
More example sentences
  • His name was Petar, and within five minutes I was jammed into his tent along with three of his companions.
  • Sometimes as many as 500 students jam themselves into an auditorium for a California Scholarship Federation meeting.
  • It turned out to be a large roost of house sparrows all trying to jam themselves into two small trees making a racket.
Synonyms
crowd, pack, pile, press, squeeze, cram;
throng, occupy, fill, overfill, overcrowd;
obstruct, block, clog, congest;
North American mob
1.1Push (something) roughly and forcibly into position or a space: he jammed his hat on
More example sentences
  • Ending his game, Tim stepped down from the platform, snatching his hat and jamming it atop his head, while swinging his bag over his shoulder simultaneously.
  • My hair stood at different angles, and I jammed my Yankees hat over my head.
  • She tied up her hair in a bun and jammed a shapeless felt hat down over it.
1.2 [with object] Crowd on to (a road or area) so as to block it: the streets were jammed with tourist coaches
More example sentences
  • AMERICAN POETRY is at something of a crossroads, and the roads leading there are jammed with traffic.
  • The East Lancashire Road was jammed with commuters trying to avoid the motorway.
  • It's no better on the roads, jammed by 7.30 am, with huge seas of traffic for most of the day, sometimes until 9 o'clock at night.
1.3 [with object] Cause (telephone lines) to be continuously engaged with a large number of calls: listeners jammed a radio station’s switchboard with calls
More example sentences
  • Telephone lines were jammed and communication with the rest of the country was effectively cut off for several hours.
  • Listeners from all over the North East jammed the lines to ask Mike Parr to have the song put on the radio station's playlist.
  • Telephone lines became jammed as distraught relatives tried to check up on loved-ones but that did not stop the rumours spreading as attention turned to who was responsible.
2Become or make unable to move or work due to a part seizing up or becoming stuck: [no object]: the photocopier jammed [with object]: the doors were jammed open
More example sentences
  • The door seemed to be jammed and it moved very slowly as I pushed with all my might.
  • On one beach, hemmed in by cliffs on either side and palm trees at the back, some Grenadians are playing cricket, three sticks jammed into the sand for stumps.
  • With a hoe-blade unrolled from her canvas, jammed onto the walking stick, she cleared a patch of low white stumps.
Synonyms
stick, become stuck, catch, seize (up), become immobilized, become unable to move, become fixed, become wedged, become lodged, become trapped
immobilize, paralyse, disable, cripple;
deactivate, put out of action, make inoperative;
stop, halt, bring to a halt, bring to a standstill
2.1 [with object] Make (a broadcast or other electronic signal) unintelligible by causing interference: they were jamming broadcasts by the pirate radio ships
More example sentences
  • People don't want their cell phone signals jammed, I am certain.
  • The basic idea is that you carry a personalized device that jams the signals from all the RFID tags on your person until you authorize otherwise.
  • The FCC argues that jamming mobile phone signals is theft of airwaves - but, more importantly, the dangers of someone missing an important call outweigh any benefit of silence.
3 [no object] informal Improvise with other musicians, especially in jazz or blues: he had the opportunity to jam with Atlanta blues musicians
More example sentences
  • As the band got into their set, there were so many musicians jamming on a single song, it was like the finale of a Live Aid concert.
  • To the delight of the crowd the pair jammed out a selection of Bob Marley classics and Fugees hits.
  • They played old and new hits, got the audience jumping over and over again, and ended it by going back into the crowd and jamming for 20 minutes or so.

noun

Back to top  
1An instance of a thing seizing or becoming stuck: paper jams
More example sentences
  • I'd prefer to further my skills and career - not occupy myself hunched over a photocopier, when the biggest excitement of my working day is a paper jam.
  • There's a paper jam, and she's got some scissors that you can actually see there on the counter, and she's trying to fix the paper jam.
  • Election officials complain of paper jams, maintenance problems at the polling places, and high costs of printing and ballot management.
1.1 short for traffic jam. she was held up in a jam on the M25
More example sentences
  • But the traffic tailbacks and jams, which stretched right back into York, lasted well into the rush hour.
  • Yesterday, motorists were caught in jams as he carried out his protest.
  • All but one of the four northbound motorway lanes had to be closed down for several hours creating jams and tailbacks.
Synonyms
tailback, line, stream, hold-up, obstruction, congestion, bottleneck, stoppage;
North American gridlock
informal snarl-up
1.2 Climbing A hold obtained by jamming a part of the body such as a hand or foot into a crack in the rock.
More example sentences
  • Once you're over the initial difficulties, the route follows a nice crack that I used for left foot and hand jams.
  • Next were some sweet crack seams where hand jams were somewhat necessary.
  • For two solid pitches of great climbing, you combine laybacking, finger and hand jams, and friction moves to make your way up the corner system.
2 informal An awkward situation or predicament: I’m in a jam
More example sentences
  • In a jam like this, it's certainly OK to help your girl save face.
  • Are you as helpful as you can be when your pal is in a jam?
  • If there is one message from what's happened, it is that when this Government is in a jam, it volunteers little except under duress.
3 (also jam session) An improvised performance by a group of musicians, especially in jazz or blues.
More example sentences
  • Just as jazz musicians improvise in a jam session, two or more painters hold a visual dialogue where non-verbal expression provokes a response that in turn provokes a reaction from a partner.
  • So the musicians entered or departed one by one, giving way to each other in the course of performance, not that different from a jazz jam session.
  • Hear the best of Floyd, from record-perfect copies of your favorite songs to their psychedelic space jams.
3.1(Especially in dance or urban music) a song or track: an ultra catchy jam, driven by the drums but given substance by the interjection of horns the band dedicated about a quarter of the set to new jams
More example sentences
  • The car's new sound system can easily kick out the high-volume jams with the added noise of driving without a roof.
  • It was nice of Lenny Kravitz to dust off some new jams for us at halftime there.
  • A would-be country performer, she whipped out her favorite jam, "Superbass", and impressed!

Origin

early 18th century: probably symbolic; compare with jag1 and cram.

Phrases

jam on the brakes

Operate the brakes of a vehicle suddenly and forcibly, typically in response to an emergency.
More example sentences
  • Just as he reached the Avenue, he suddenly jammed on the brakes, sending us flying towards the rear window.
  • Instead of racing up to stop signs and red lights, jamming on the brakes, and then accelerating quickly when it is your turn to go, back off of the gas as you approach the stopping point and accelerate gradually when you pull out.
  • Azrael had jammed on the brakes, sending the automobile into a short skid forward, the sudden movement tensing his new muscles and flesh quickly.

Derivatives

jammer

noun
More example sentences
  • These guys are real nasty jammers, they do gypsy reggae, Latino ska funk, you name it.
  • And according to several news reports, those who are bothered by cell phone rudeness are increasingly turning to jammers - devices that prevent making and receiving cell phone calls.
  • In fact, for the most part the bombers looked just alike, but instead of having the large heavy bombs loaded in the bomb bays, the radar countermeasure aircraft carried high voltage jammers.

Definition of jam in:

There are 2 main definitions of jam in English:

jam2

Line breaks: jam
Pronunciation: /dʒam
 
/

noun

[mass noun]
1A sweet spread or conserve made from fruit and sugar boiled to a thick consistency: strawberry jam [as modifier]: jam doughnuts
More example sentences
  • You can then sprinkle the petit suisse with sugar or strawberry jam.
  • Fresh thick slices of loaf bread, generously spread with strawberry jam, washed down with strong sweet tea just have to be eaten outdoors to be really enjoyed.
  • The sandwich was well up to expectations and this was followed by a warm and very fresh fruit scone which crumbled as we spread it with strawberry jam and cream.
Synonyms
1.1British Used in reference to something easy or pleasant: they want it all, both ways and with jam on the top
More example sentences
  • However, rather than adopt a ‘gruel for all’ approach, he has opted to ‘add jam on top’ for the poorest.
  • It seems you're just not interested in the bread and butter; only the jam.

verb (jam, jamming, jammed)

[with object] Back to top  
Make (fruit) into jam.

Origin

mid 18th century: perhaps from jam1.

Phrases

jam tomorrow

British A pleasant thing which is often promised but rarely materializes: a promise of jam tomorrow wasn’t enough to satisfy them
[phrase from Lewis Carroll's Through the Looking Glass (1871)]
More example sentences
  • Policy holders want cash today, not the promise of jam tomorrow, and if people don't appreciate that then they are out of touch.
  • He should realise that promises of jam tomorrow are not helping shopkeepers in his area to swallow difficulties forced on them by the loss of parking spaces.
  • Unfortunately, in the case of human and civil rights, promises of jam tomorrow are simply not good enough.

Definition of jam in: