—v.t. 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 fol. by on): 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. a. to interfere with (radio signals or the like) by sending out other signals of approximately the same frequency.
b. (of radio signals or the like) to interfere with (other signals).
9. to play (a piece) in a freely improvised, swinging way; jazz up: to jam both standard tunes and the classics. 10. Naut.to head (a sailing ship) as nearly as possible into the wind without putting it in stays or putting it wholly aback.
—v.i. 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. Jazz.to participate in a jam session.
—n. 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. See jam session.
Pronunciation: ( jam),[key] —n. 1. a preserve of whole fruit, slightly crushed, boiled with sugar: strawberry jam. 2. put on jam,Australian Slang.to adopt a self-important manner or use affected speech.