jam¹ (jăm)

v., jammed, jam·ming, jams.

v.tr.

1. To drive or wedge forcibly into a tight position: jammed the cork in the bottle.
2. To activate or apply (a brake) suddenly. Often used with on: jammed the brakes on.
3. To cause (moving parts, for example) to lock into an unworkable position: jammed the typewriter keys.
4. 1. To pack (items, for example) to excess; cram: jammed my clothes into the suitcase.
   2. To fill (a container or space) to overflowing: I jammed the suitcase with clothes. Fans jammed the hallway after the concert.
5. To block, congest, or clog: a drain that was jammed by debris.
6. To crush or bruise: jam a finger.
7. Electronics. To interfere with or prevent the clear reception of (broadcast signals) by electronic means.
8. Baseball. To throw an inside pitch to (a batter), especially to prevent the batter from hitting the ball with the thicker part of the bat.

v.intr.

1. To become wedged or stuck.
2. To become inoperable: The computer keyboard jammed.
3. To force one's way into or through a limited space.
4. Music. To participate in a jam session.
5. Basketball. To make a dunk shot.

n.

1. The act of jamming or the condition of being jammed.
2. A crush or congestion of people or things in a limited space: a traffic jam.
3. A trying situation. See synonyms at predicament.

[Origin unknown.]

jammable jam'ma·ble adj.
jammer jam'mer n.

jam² (jăm)
n.
A preserve made from whole fruit boiled to a pulp with sugar.

[Possibly from JAM¹.]

jammy jam'my adj.

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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