jam

Etymology 1

First attested in the early 18th c. as a verb meaning “to press, be pressed, be wedged in”. Compare dialectal jammock (“to press, squeeze, crush into a soft mass, chew food"; also "a soft, pulpy substance”). Perhaps from Middle English chammen, champen ("to bite upon something, gnash the teeth"; whence modern champ, chomp), of uncertain origin; probably originally onomatopoeic.

noun

1. (less common in the US) A sweet mixture of fruit boiled with sugar and allowed to congeal. Often spread on bread or toast or used in jam tarts.
2. (countable) A difficult situation.
   It's a blackmail ring, and the district attorneys get a share of the loot. […] Well, they got him in the same kind of jam, and soaked him to the tune of three hundred and eighty-six thousand. 1928, Upton Sinclair, Boston
   She was married when we first met / Soon to be divorced / I helped her out of a jam, I guess / But I used a little too much force 1975, Bob Dylan (lyrics and music), “Tangled Up in Blue”
   Where, where is my common sense? / How did I get in a jam like this? 1977, David Byrne (lyrics and music), “Uh-Oh, Love Comes to Town”, in Talking Heads: 77, performed by Talking Heads
3. (countable) A blockage, congestion, or immobilization.
   A traffic jam caused us to miss the game's first period.
   a jam of logs in a river
   According to Boeing, in the history of this elevator design (which exists on all Boeing DC-9/MD-80 series and 717 model airplanes), this accident was the first notification that Boeing had received of an elevator jam occurring on an airplane exposed to ground gusts lower than 65 kts. Boeing noted that the elevator design first entered service in 1965 on the then-Douglas DC-9 airplane. 14 February 2019, National Transportation Safety Board, “1.3.2.3 Elevator Design Standard for Ground Gust Loads”, in Aircraft Accident Report: Runway Overrun During Rejected Takeoff, Ameristar Air Cargo, Inc., dba Ameristar Charters, flight 9363, Boeing MD-83, N786TW, Ypsilanti, Michigan, March 8, 2017, archived from the original on 2022-07-02, page 12
4. (countable, popular music) An informal, impromptu performance or rehearsal.
5. (countable, by extension, informal) A song; a track.
   The result is an outstanding assortment of sophisticated, sexy and hip-hop-tinged R&B grooves, ballads and party jams. 2001, Jet, volume 100, number 22, page 25
6. (countable, by extension) An informal event where people brainstorm and collaborate on projects.
   We came up with some new ideas at the game jam.
   […] a day at new Farm Park with an art jam, fursuit games, and a nerf war, ending in the evening at the strike Wintergarden bowling center. 2017, Fred Patten, Furry Fandom Conventions, 1989-2015, page 92
7. (countable, slang) That which one particularly prefers, desires, enjoys, or cares about.
   Teaching is my jam.
8. (countable, baseball) A difficult situation for a pitcher or defending team.
   The pitcher's in a jam now, having walked the bases loaded with the cleanup hitter coming to bat.
9. (countable, basketball) A forceful dunk.
10. (countable, roller derby) A play during which points can be scored.
    Toughie scored four points in that jam.
11. (climbing, countable) Any of several maneuvers requiring wedging of an extremity into a tight space.
    I used a whole series of fist and foot jams in that crack.
12. (Australia) The tree Acacia acuminata, with fruity-smelling hard timber.
13. (UK, slang) Luck.
    He's got more jam than Waitrose.
14. (Canada, slang) balls, bollocks, courage, machismo
    I don't think he has the jam.
15. (slang) Sexual relations or the contemplation of them.

verb

1. To get something stuck, often (though not necessarily) in a confined space.
   My foot got jammed in a gap between the rocks.
   Her poor little baby toe got jammed in the door.
   I jammed the top knuckle of my ring finger.
2. To brusquely force something into a space; to cram, to squeeze.
   They temporarily stopped the gas tank leak by jamming a piece of taffy into the hole.
   The rush-hour train was jammed with commuters.
   Jamm’d in at midnight, in cold winter weather, 1779, George Colman, Farewell Epilogue, spoken at Wynnstay after the representation of Cymbeline and The Spanish Barber, 22 January, 1779, in Prose on Several Occasions: Accompanied with Some Pieces in Verse, London: T. Cadel, 1787, Volume 3, p. 283, Since the new post-horse tax, I dare engage That some folks here have travell’d in the Stage
3. To render something unable to move.
   Considering the results of the CFD wind simulation, the NTSB designed several series of static and dynamic elevator load tests to determine what conditions, consistent with the known circumstances of the accident, could enable the inboard actuating crank and links of the right elevator's geared tab to move beyond their normal range of travel and become locked in an overcenter position (and, as a result, jam the right elevator). 14 February 2019, National Transportation Safety Board, “2.3.3 Elevator Load Testing”, in Aircraft Accident Report: Runway Overrun During Rejected Takeoff, Ameristar Air Cargo, Inc., dba Ameristar Charters, flight 9363, Boeing MD-83, N786TW, Ypsilanti, Michigan, March 8, 2017, archived from the original on 2022-07-02, page 56
4. To cause congestion or blockage. Often used with "up".
   A single accident can jam the roads for hours.
5. To block or confuse a radio or radar signal by transmitting a more-powerful signal on the same frequency.
   The government jams foreign propaganda broadcasts.
   The airstrike suffered minimal casualties because electronic-warfare aircraft were jamming the enemy air-defense radars.
6. (baseball) To throw a pitch at or near the batter's hands.
   Jones was jammed by the pitch.
7. (basketball) To dunk.
8. (music) To play music (especially improvisation as a group, or an informal unrehearsed session).
9. To injure a finger or toe by sudden compression of the digit's tip.
   When he tripped on the step he jammed his toe.
10. (roller derby) To attempt to score points.
    Toughie jammed four times in the second period.
11. (nautical, transitive) To bring (a vessel) so close to the wind that half her upper sails are laid aback.
    It won't do to jam her,” answered Stone ;" but it might be worth findin' out if th' Hope won't lie closer than t' other can." Half a point ----" (Can we date this quote?), William Clark Russell, The Golden Hope
12. (Canada, informal) To give up on a date or some other joint endeavour; to stand up, chicken out, jam out.
13. (colloquial) To be of high quality.
    I love this song! This song jams!

Etymology 2

Persian or Hindi, meaning "garment, robe;" see جامه (“garment”). Related to pajamas.

noun

1. (dated) A kind of frock for children.

Etymology 3

noun

1. (mining) Alternative form of jamb