(jam) v. jammed, jam·ming v.t.
1. To press or force into a tight place or position; wedge or squeeze in.
2. To fill and block up by crowding: to jam a corridor.
3. To bruise or crush by violent pressure.
4. To cause (a machine, part, etc.) to become wedged or stuck fast so that it cannot work.
5. In radio, to interfere with (a broadcast, station, etc.) by transmitting on the same wavelength.
—v.i.
6. To become wedged; stick fast.
7. To press or wedge; push: The crowd jammed into the room.
8. In jazz music, to improvise; also, to take part in a jam session.
—noun
1. A number of people or objects closely crowded; a crush; the act of jamming.
2. A mass of logs, ice, etc., blocked in a stream. See synonyms under THRONG.
—adverb Completely: jam full. ♦ Homophone: jamb. [Related to CHAMP¹] Synonyms (verb): crowd, crush, force, pack, press, push, squeeze, throng. See HUSTLE. Antonyms: ease, free, liberate, loosen, release, relieve.

(jam) noun
A pulpy, sweet conserve of fruit boiled with sugar: distinguished from jelly. ♦ Homophone: jamb. [? <JAM¹, v.]