jam

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A preserve made from whole fruit boiled to a pulp with sugar.
• intransitive verb To drive or wedge forcibly into a tight position.
• intransitive verb To activate or apply (a brake) suddenly. Often used with on:
• intransitive verb To cause (moving parts, for example) to lock into an unworkable position.
• intransitive verb To pack (items, for example) to excess; cram.
• intransitive verb To fill (a container or space) to overflowing.
• intransitive verb To block, congest, or clog.
• intransitive verb To crush or bruise.
• intransitive verb Electronics To interfere with or prevent the clear reception of (broadcast signals) by electronic means.
• intransitive verb 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.
• intransitive verb To become wedged or stuck.
• intransitive verb To become locked or stuck in an unworkable position.
• intransitive verb To force one's way into or through a limited space.
• intransitive verb Music To participate in a jam session.
• intransitive verb Basketball To make a dunk shot.
• noun The act of jamming or the condition of being jammed.
• noun A crush or congestion of people or things in a limited space.
• noun A trying situation. synonym: predicament.

from The Century Dictionary.

• noun A conserve of fruits prepared by boiling them to a pulp in water with sugar.
• noun A crush; a squeeze; pressure by thrusting or crowding.
• noun A crowd of objects irregularly and tightly pressed together by arrest of their movement; a block, as of people, vehicles, or floating logs.
• noun Another spelling of jamb, 4.
• To press; squeeze; thrust or press down or in with force or violence; thrust or squeeze in so as to stick fast; press or crowd in such a manner as to prevent motion or hinder extrication.
• To fill full; block up; prevent the movement of by pressure, crowding, etc.
• To tread hard or make firm by treading, as land is trodden hard by cattle.
• To become wedged together or in place, as by violent impact; stick fast: as, the door jams.
• To push (a bill or measure) through the regular routine of a legislative body by the brute force of a majority controlled by ‘the machine,’ without proper consideration or discussion. [Political slang.]
• noun The title of certain native chiefs in northwestern India.
• noun In England, a kind of dress worn by children: so called from the Hindu jama, a long muslin gown worn in India by both Mohammedans and Hindus.
• noun An abbreviation of Jamaica.
• noun An extra pool in the game of napoleon.
• To smear or spread with jam: as, a slice of bread thickly jammed.
• To become jam; thicken to the consistency of jam.

from the GNU version of the Collaborative International Dictionary of English.

• noun A kind of frock for children.
• noun (Mining) See jamb.
• intransitive verb To become stuck so as not to function.
• intransitive verb (Music) To play an instrument in a jam session.
• intransitive verb To crowd together; -- usually used with together or in.
• transitive verb To press into a close or tight position; to crowd; to squeeze; to wedge in; to cram.
• transitive verb colloq. To crush or bruise.
• transitive verb (Naut.) To bring (a vessel) so close to the wind that half her upper sails are laid aback.
• transitive verb To block or obstruct by packing too much (people or objects) into.
• transitive verb (Radio) To interfere with (a radio signal) by sending other signals of the same or nearby frequency.
• transitive verb To cause to become nonfunctional by putting something in that blocks the movement of a part or parts.
• noun A mass of people or objects crowded together; also, the pressure from a crowd; a crush
• noun colloq. An injury caused by jamming.
• noun informal A difficult situation.
• noun A preserve of fruit boiled with sugar and water; also called jelly