From WordNet (r) 3.0 (2006):
jam
n 1: preserve of crushed fruit
2: informal terms for a difficult situation; "he got into a
terrible fix"; "he made a muddle of his marriage" [syn:
fix, hole, jam, mess, muddle, pickle, kettle of
fish]
3: a dense crowd of people [syn: crush, jam, press]
4: deliberate radiation or reflection of electromagnetic energy
for the purpose of disrupting enemy use of electronic devices
or systems [syn: jamming, electronic jamming, jam]
v 1: press tightly together or cram; "The crowd packed the
auditorium" [syn: throng, mob, pack, pile, jam]
2: push down forcibly; "The driver jammed the brake pedal to the
floor"
3: crush or bruise; "jam a toe" [syn: jam, crush]
4: interfere with or prevent the reception of signals; "Jam the
Voice of America"; "block the signals emitted by this
station" [syn: jam, block]
5: get stuck and immobilized; "the mechanism jammed"
6: crowd or pack to capacity; "the theater was jampacked" [syn:
jam, jampack, ram, chock up, cram, wad]
7: block passage through; "obstruct the path" [syn: obstruct,
obturate, impede, occlude, jam, block, close up]
[ant: disengage, free]