jam

¹ American  

[jam] / dʒæm /

verb (used with object)

jammed, jamming

1. to press, squeeze, or wedge tightly between bodies or surfaces, so that motion or extrication is made difficult or impossible.

   The ship was jammed between two rocks.

2. to bruise or crush by squeezing.

   She jammed her hand in the door.

3. to fill too tightly; cram.

   He jammed the suitcase with clothing.

4. to press, push, or thrust violently, as into a confined space or against some object.

   She jammed her foot on the brake.

5. to fill or block up by crowding; pack or obstruct.

   Crowds jammed the doors.

6. to put or place in position with a violent gesture (often followed byon ).

   He jammed his hat on and stalked out of the room.

7. to make (something) unworkable by causing parts to become stuck, blocked, caught, displaced, etc..

   to jam a lock.

8. Radio.

   1. to interfere with (radio signals or the like) by sending out other signals of approximately the same frequency.

   2. (of radio signals or the like) to interfere with (other signals).

9. Music. to play (a piece) in a freely improvised, swinging way; jazz up.

   to jam both standard tunes and the classics.

10. Nautical. to head (a sailing ship) as nearly as possible into the wind without putting it in stays or putting it wholly aback.

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verb (used without object)

jammed, jamming

1. to become stuck, wedged, fixed, blocked, etc..

   This door jams easily.

2. to press or push, often violently, as into a confined space or against one another.

   They jammed into the elevator.

3. (of a machine, part, etc.) to become unworkable, as through the wedging or displacement of a part.

4. Music. to participate in a jam session.

5. to collaborate informally, freely, and creatively with others.

   Our department was jamming on a customer project and didn't have time to prep a demo for the conference.

6. Slang.

   1. to make good progress; do well.

      Working alone is awesome when I’m jamming on a project that I love.

   2. to thoroughly like or enjoy something.

      The colors came out rather well, but I'm just not jamming on the actual image.

noun

1. the act of jamming or the state of being jammed.

2. a mass of objects, vehicles, etc., jammed together or otherwise unable to move except slowly.

   a log jam; a traffic jam.

3. Informal. a difficult or embarrassing situation; fix.

   He got himself into a jam with his boss.

4. Music.

   1. jam session.

   2. a piece of music.

      On November 18, the 16-year-old star dropped her new jam, marking an evolution in her sound and style.

5. Slang.

   1. something that one particularly likes, enjoys, or does well: Since math is not my jam, I’ll let y’all figure out the rest.

      Seriously, a huge meat patty and garlic fries are pretty much my jam after a day outside.

      Since math is not my jam, I’ll let y’all figure out the rest.

   2. something that one finds pleasant or easy.

      Life isn't all jam for me just now.

6. a contest, meeting, or conference at which people collaborate informally, freely, and creatively.

   People from 158 countries registered for the jam and shared their ideas for action to improve the quality of life in the world’s cities.

jam ² American  

[jam] / dʒæm /

noun

1. a preserve of whole fruit, slightly crushed, boiled with sugar.

   strawberry jam.

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idioms

1. put on jam, to adopt a self-important manner or use affected speech.

Jam. ³ American  

abbreviation

1. Jamaica.

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jam ¹ British  

/ dʒæm /

verb

1. (tr) to cram or wedge into or against something

   to jam paper into an incinerator

2. (tr) to crowd or pack

   cars jammed the roads

3. to make or become stuck or locked

   the switch has jammed

4. to activate suddenly (esp in the phrase jam on the brakes )

5. (tr) to block; congest

   to jam the drain with rubbish

6. (tr) to crush, bruise, or squeeze; smash

7. radio to prevent the clear reception of (radio communications or radar signals) by transmitting other signals on the same frequency

8. slang (intr) to play in a jam session

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noun

1. a crowd or congestion in a confined space

   a traffic jam

2. the act of jamming or the state of being jammed

3. informal a difficult situation; predicament

   to help a friend out of a jam

4. See jam session

jam ² British  

/ dʒæm /

noun

1. a preserve containing fruit, which has been boiled with sugar until the mixture sets

2. slang something desirable

   you want jam on it

3. the principle of living for the moment

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Jam. ³ British  

abbreviation

1. Jamaica

2. Bible James

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jam More Idioms  

1. see under get in a bind.

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Other Word Forms

• jamlike adjective
• jammer noun
• jammy adjective

Etymology

Origin of jam¹

First recorded in 1700–10; apparently imitative; champ ¹, dam ¹

Origin of jam²

First recorded in 1730–40; perhaps special use of jam ¹ (in the sense “to bruise or crush by squeezing”)

Explanation

To jam is to squeeze something tightly into a space, the way your friends might jam themselves into your tiny car. You might have to jam an extra row of books onto your bookshelf when you run out of room. Another way to jam is to get stuck, and a jam can be a dense bunch of stuck people or things, like a traffic jam. If you play a musical instrument, you might jam, or casually improvise, with other musicians. And of course the jam you spread on your toast is a delicious, sweet fruit preserve.

Example Sentences

There was a sweet irony watching them close the set with “Intro,” a modest instrumental jam from their debut that has, through well-paying commercial placements, become their calling card to mainstream pop.

From Los Angeles Times • Apr. 11, 2026

He’s concerned all the social-media talk about tax strikes will lead to some people getting in a jam because they didn’t understand the rules.

From MarketWatch • Apr. 6, 2026

“As soon as we did, we were staying up late making music with these models—was like the old jam sessions, just entirely on a computer.”

From The Wall Street Journal • Mar. 28, 2026

Further along the table, a three-tiered honey cake sits near a wholemeal plum cake with spiced icing, while a Swedish princess cake draws gasps of admiration with its dome of sponge, jam, custard and marzipan.

From BBC • Mar. 28, 2026

For dessert we had a peanut butter and jam sandwich or vanilla ice cream.

From "Breaking Through" by Francisco Jiménez