jam
jam — abbreviation
1. a short written form of Jamaica, used on vehicle registration plates, postal add
a short written form of Jamaica, used on vehicle registration plates, postal addresses, or official forms to save space.
The parcel was addressed to 12 Harbour Street, Kingston, Jam., with a return label from Montego Bay.
abbreviation in postal address
The minibus had a Jam. sticker on its number plate, showing it was registered in Jamaica.
On the shipping form, Lotte wrote 'Jam.' in the country field and handed it to the customs officer.
abbreviation on official forms
The guide explained that 'Jam.' on the vehicle plates stands for Jamaica, not for the capital city.
Grammar Patterns
abbreviation written as 'Jam.'
jam — noun
1. a thick, sweet spread for bread, made from fruit and sugar that are heated toget
a thick, sweet spread for bread, made from fruit and sugar that are heated together until the mixture thickens and becomes firm.
Minh spread strawberry jam on his toast and poured himself a glass of orange juice.
jam spread on toast
My grandmother makes her own apricot jam every summer and gives jars to the neighbours.
A pot of raspberry jam was sitting on the kitchen table next to a loaf of fresh bread.
Do you prefer seedless raspberry jam or the kind with whole berries in it?
- strawberry jam
- raspberry jam
- spread jam
- a jar of jam
- jam sandwich
- jam tart
Grammar Patterns
(a jar of) jam
jam + noun (jam sandwich)
Usage Note
In British English 'jam' usually contains fruit pulp; in American English the term also covers clear fruit preserves sometimes called 'jelly'.
Common Mistakes
2. a long line of vehicles on a road that are moving very slowly or have stopped co
a long line of vehicles on a road that are moving very slowly or have stopped completely because there are too many of them.
Emre was forty minutes late for work because of a terrible traffic jam on the motorway.
stuck in a traffic jam
The accident on the bridge caused a jam that stretched back for over ten kilometres.
A broken-down lorry near the tunnel entrance created a massive jam during the evening rush hour.
The new traffic lights were meant to reduce jams at the junction, but they only made things worse.
reduce / cause jams
- traffic jam
- stuck in a jam
- cause a jam
- rush-hour jam
- motorway jam
- gridlock
a traffic jam so bad that no vehicles can move in any direction
- tailback
British term for a long line of stationary traffic
- congestion
uncountable term for heavy, slow traffic
Grammar Patterns
be (stuck) in a jam
cause a jam
Usage Note
Often used in the compound noun 'traffic jam'. The single word 'jam' can also mean a traffic jam when the context is clear.
Common Mistakes
3. when a machine part gets trapped or blocked, causing the machine to stop working
when a machine part gets trapped or blocked, causing the machine to stop working correctly.
The photocopier had a paper jam, so Wren had to open the tray and pull out the wrinkled sheet.
paper jam in photocopier
A jam in the conveyor belt stopped the entire factory production line for nearly an hour.
Before calling the repair person, try clearing the jam yourself by following the instructions on the screen.
clear / fix a jam
A paper jam in the printer caused her report to come out with half the page blank and wrinkled.
- paper jam
- clear a jam
- cause a jam
- a jam in the printer
Grammar Patterns
a jam in [machine]
clear a jam
Usage Note
Most commonly used with printers and photocopiers ('paper jam'). The verb phrase 'clear a jam' means to remove the stuck object so the machine works again.
4. a difficult or unpleasant situation that is hard to escape from, especially one
a difficult or unpleasant situation that is hard to escape from, especially one caused by one's own actions or bad luck.
Valentina forgot her passport at the hotel and found herself in a real jam at the airport check-in counter.
be in a jam
The company got into a financial jam after their biggest customer cancelled a major order without warning.
Tyler knew he was in a jam when the exam covered topics he had not studied at all.
A little help from his cousin got Minh out of the jam he created by double-booking the venue.
get out of a jam
- be in a jam
- get into a jam
- get out of a jam
- real jam
- financial jam
Grammar Patterns
be in a jam
get into a jam
get out of a jam
Usage Note
Always used with 'in' or 'into' ('in a jam', 'into a jam'). More informal than 'in trouble' or 'in a difficult situation'. Similar to 'in a fix' or 'in a bind'.
5. a situation where so many people are packed into a space that it becomes very ti
a situation where so many people are packed into a space that it becomes very tight and uncomfortable.
There was a real jam of commuters trying to squeeze into the last train carriage before the doors closed.
a jam of [people]
Ayana could barely breathe in the jam of festival-goers packed shoulder to shoulder near the main stage.
The narrow market alley was a solid jam of shoppers pushing past each other with bags and umbrellas.
During the New Year countdown, Times Square became such a jam that people could barely lift their arms.
- a jam of people
- a jam of commuters
- a solid jam
Grammar Patterns
a jam of [people]
Usage Note
Describes a crowded state, not the crowd itself. For the crowd as a blocking mass, see the BLOCKING CROWD sense (noun 7).
6. an informal musical performance in which musicians play together without followi
an informal musical performance in which musicians play together without following a strict plan or set list, often inventing melodies and rhythms on the spot.
After the concert, the band members stayed behind for a late-night jam in the hotel lobby.
late-night jam
Mathieu invited a few friends from the jazz club to his apartment for a jam on Saturday afternoon.
The weekly open-mic night turned into a fantastic jam when three guitarists and a drummer jumped on stage together.
Haruto recorded the whole jam on his phone so the group could listen back and improve their improvisation.
- have a jam
- jam session
- late-night jam
- jazz jam
- join a jam
- jam session
the full compound noun; more formal than just 'jam'
- improv session
used in jazz and theatre, emphasises improvisation
- free play
less common; emphasises the lack of rules
Grammar Patterns
have a jam
jam session
Usage Note
Often used in the compound 'jam session'. As a single word, the context (music, musicians, instruments) makes the meaning clear.
7. a tightly packed crowd that stops people from getting past, because it fills a d
a tightly packed crowd that stops people from getting past, because it fills a doorway, street, or passage completely.
A solid jam of protesters blocked the entrance to the government building, so the staff could not get inside.
a jam of [people] blocking passage
A jam of onlookers blocked the stairs, so Élise could not reach the emergency exit.
Guards tried to break up the jam of fans pushing against the barriers after the show.
A jam of journalists crowded the hallway outside the courtroom, making it hard for the lawyers to get through.
- a jam of people
- a jam of fans
- solid jam
- break up a jam
- logjam
originally a pile of floating logs blocking a river; now used for any blocked situation
- bottleneck
a narrow point that causes congestion, not the crowd itself
Grammar Patterns
a jam of [people/crowd]
Usage Note
Distinguish from the CROWDED SPACE sense (noun 5): this sense focuses on the crowd itself as a physical barrier that prevents movement, while sense 5 focuses on the uncomfortable state of being packed together.
be in a jam
idiomto be in a difficult or troublesome situation that is hard to escape from.
Adina was in a jam when her car broke down on a lonely mountain road with no phone signal.
jam tomorrow
idiomsomething good that is promised for the future but never actually arrives or is always delayed.
The manager kept promising us a bonus, but it was always jam tomorrow — never today.
money for jam
idiommoney that is earned very easily, with little or no effort.
Getting paid five hundred dollars just to water the neighbour's plants for a week was money for jam.
Money that you get for doing something that requires almost no work.
Maya got paid $200 just for watering the plants—money for jam.
Is fixing that simple leak really money for old rope?
jam — verb
1. to become fixed in one position so that movement is impossible, or to force some
to become fixed in one position so that movement is impossible, or to force something into a position where it cannot move.
The window had not been opened for years, and the frame had jammed shut in its tracks.
intransitive: thing jams
Ayesha jammed a towel under the door to keep the cold draught from blowing into the bedroom.
The lift doors kept jamming halfway closed, so the building manager called an engineer to inspect them.
Lotte jammed a piece of cardboard under the wobbly table leg to stop it from rocking on the uneven floor.
jam [object] under [something]
- jam shut
- jam open
- jam under
- jam in
- get jammed
- become jammed
Grammar Patterns
something jams
jam something in/on
get jammed
Usage Note
Frequently used in the passive: 'get jammed', 'be jammed'. The object that is stuck can be a moving part of a machine (drawer, window, door) or an item wedged in place.
Common Mistakes
2. to send out strong radio waves or other signals that stop radio, television, pho
to send out strong radio waves or other signals that stop radio, television, phone, or radar transmissions from getting through to their intended receivers.
The military used a special device to jam the enemy's radar during the night operation.
jam [equipment]
Protesters brought equipment that could jam the police radio frequencies in the area.
Thieves sometimes use portable jamming devices to block the signals of car key fobs so that doors cannot be locked.
The government accused the foreign intelligence agency of trying to jam satellite communications during the crisis.
jam [communications]
- jam signals
- jam radar
- jam communications
- jam frequencies
- jamming device
- block
more general; can mean preventing any type of transmission, not just by radio interference
- interfere with
less specific; can mean causing partial disruption rather than full blocking
- disrupt
to interrupt or throw into disorder, not necessarily to stop completely
Grammar Patterns
jam [signals]
jam [equipment]
Usage Note
Almost always transitive — you jam a signal, frequency, or device. The noun form is 'jamming' (e.g., 'signal jamming equipment').
3. to play music informally with other people, making up melodies, rhythms, and har
to play music informally with other people, making up melodies, rhythms, and harmonies as you go rather than following a written score.
Every Thursday evening, a group of local musicians gets together to jam in the basement of the old theatre.
jam together / get together to jam
Emre jammed on his electric guitar for hours with a bassist he had met at the record shop that afternoon.
The jazz trio invited anyone who played an instrument to come up and jam with them during the second set.
jam with [someone]
Wren loves to jam on the piano late at night when the house is quiet and nobody can hear her.
- jam with
- jam together
- jam on [instrument]
- get together to jam
- jam session
- improvise
more formal and broader in meaning; used in theatre and dance as well as music
- play by ear
to play music without sheet music, not necessarily with others
- freestyle
used mostly for rap and hip-hop improvisation
- rehearse
to practise music following a plan or score
Grammar Patterns
jam with [someone]
jam on [instrument]
jam together
Usage Note
Always intransitive — you do not 'jam a song'; you 'jam' (play) or 'jam on a song' (improvise over it). The object is a musical context or instrument, introduced by a preposition.
4. to push or force something into a space that is too small or too tight for it, u
to push or force something into a space that is too small or too tight for it, using effort or pressure.
Tyler jammed his suitcase into the overhead bin and had to push hard to close the latch.
jam [object] into [space]
Rania jammed another book onto the already overflowing shelf, knocking a pile of papers to the floor.
The movers jammed the sofa through the narrow doorframe, leaving scuff marks on both sides of the wall.
Ayesha jammed the key into the rusty lock and turned it with both hands until she heard a click.
jam [object] into [object]
- jam into
- jam in
- jam together
- jam through
- jam down
Grammar Patterns
jam something into/in [space]
jam something together
Usage Note
The preposition 'into' is more common than 'in' when emphasising the forceful nature of the action. 'Jam together' means to press two or more things tightly against each other.
5. to fill a space so completely that there is hardly any room left, or for a space
to fill a space so completely that there is hardly any room left, or for a space to become so full that nothing else can fit.
The concert hall was jammed with fans who had queued since early morning to see the band perform.
passive: be jammed with [people]
Commuters jammed the platform during the morning rush, leaving no space for anyone else to stand.
Haruto's garage is so jammed with old furniture and garden tools that he cannot park his car inside anymore.
The narrow streets of the old town were jammed with tourists taking photographs of the historic buildings.
be jammed with [people]
- be jammed with
- jam full
- jam-packed
- completely jammed
Grammar Patterns
be jammed with [people/things]
jam [place]
Usage Note
Very common in the passive voice ('be jammed with [something]'). The active form is less common and often implies people doing the filling ('Fans jammed the hall').
Common Mistakes
6. to trap someone's finger, hand, toe, or other body part between two hard surface
to trap someone's finger, hand, toe, or other body part between two hard surfaces, causing a painful pinch or bruise.
Valentina accidentally jammed her finger in the car door when she was getting out of the back seat.
jam [body part] in [something]
The carpenter let out a cry of pain when he jammed his thumb against the workbench with the heavy hammer.
Minh jammed his toe on the bed frame in the dark and limped to check for swelling.
Adina jammed her hand in the car window while trying to roll it up quickly.
jam [body part] in [something]
- jam a finger
- jam a thumb
- jam a toe
- jam in the door
- jam on [something]
Grammar Patterns
jam [body part] in/on [something]
Usage Note
The object is always a body part (finger, thumb, toe, hand). The preposition 'in' is used for trapping inside something (e.g., a door), 'on' or 'against' for hitting a hard surface.
jam on
phrasal verbto apply a brake suddenly and forcefully, causing an abrupt stop.
A cat ran across the road, so Lotte jammed on the brakes and stopped just in time.
jam into
phrasal verbto push or force one's way into a space that is very full or tight.
Twenty students jammed into the tiny elevator, laughing as the doors barely closed behind them.
Word family
- jammedadjectiveB1
- jammingnounB2
- jammernounC1
- unjamverbC1
Synonym discussion
Sense: noun/1
All four words describe fruit-based spreads, but they differ in ingredients and regional use. 'Jam' (A2) is the most general term: mashed or chopped fruit boiled with sugar until soft. 'Preserve' (B2) is the broader category name in British English and often means fruit cooked in larger chunks or whole pieces; in American English it is the formal term for what is commonly called jam. 'Marmalade' (A2) is a specific type of jam made from citrus fruit — typically oranges — and includes pieces of peel for a bitter tang. 'Jelly' (A1) in American English means a clear jam made from fruit juice with no pulp; in British English 'jelly' is a wobbly dessert made from flavoured gelatine. So if you want a clear, seedless spread on your morning toast in the US, ask for 'jelly'; in the UK, ask for 'jam'.
Common collocations
Etymology
The word 'jam' first appeared in English in the early 1700s, referring to the fruit preserve. Its origin is uncertain — it may come from the idea of 'jamming' (crushing) fruit together. The sense of 'blocking or sticking' developed in the mid-1800s, probably from the same physical idea of things being pressed tight and unable to move. By the early 1900s, 'jam' was being used for a traffic blockage and a difficult situation. The musical meaning — an informal, improvised session — emerged in the 1920s and 1930s in American jazz culture, where musicians would 'jam' together (packed tightly into small clubs, improvising freely).