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.
The guide explained that 'Jam.' on the vehicle plates stands for Jamaica, not for the capital city.
文法句型
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?
文法句型
(a jar of) jam
jam + noun (jam sandwich)
用法筆記
In British English 'jam' usually contains fruit pulp; in American English the term also covers clear fruit preserves sometimes called 'jelly'.
常見錯誤
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.
- 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
文法句型
be (stuck) in a jam
cause a jam
用法筆記
Often used in the compound noun 'traffic jam'. The single word 'jam' can also mean a traffic jam when the context is clear.
常見錯誤
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.
A paper jam in the printer caused her report to come out with half the page blank and wrinkled.
文法句型
a jam in [machine]
clear a jam
用法筆記
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.
文法句型
be in a jam
get into a jam
get out of a jam
用法筆記
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.
文法句型
a jam of [people]
用法筆記
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.
- 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
文法句型
have a jam
jam session
用法筆記
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.
- 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
文法句型
a jam of [people/crowd]
用法筆記
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.
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.
文法句型
something jams
jam something in/on
get jammed
用法筆記
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.
常見錯誤
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.
- 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
文法句型
jam [signals]
jam [equipment]
用法筆記
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.
Wren loves to jam on the piano late at night when the house is quiet and nobody can hear her.
- 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
文法句型
jam with [someone]
jam on [instrument]
jam together
用法筆記
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.
文法句型
jam something into/in [space]
jam something together
用法筆記
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.
文法句型
be jammed with [people/things]
jam [place]
用法筆記
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').
常見錯誤
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.
文法句型
jam [body part] in/on [something]
用法筆記
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.