First attested in the early 18th c. as a verb meaning “to press, be pressed, be wedged in”. Compare dialectaljammock(“to press, squeeze, crush into a soft mass, chew food"; also "a soft, pulpy substance”). Perhaps fromMiddle Englishchammen,champen("to bite upon something, gnash the teeth"; whence modernchamp,chomp), of uncertain origin; probably originally onomatopoeic.
The "performance" sense is first attested with regards to jazz in 1929, and its origin, though uncertain, is likely metaphorical, "something sweet made by the combination of many things", with influence fromjamboree.
(less common in the US and Canada) A sweet mixture of fruit boiled with sugar and allowed to congeal. Often spread on bread or toast or used injam tarts.
It's a blackmail ring, and the district attorneys get a share of the loot.[…] Well, they got him in the same kind ofjam, and soaked him to the tune of three hundred and eighty-six thousand.
ajam on the 101 South, blocking the two right lanes[radio report]
ajam of logs in a river
2019 February 14,National Transportation Safety Board, “1.3.2.3 Elevator Design Standard for Ground Gust Loads”, inAircraft 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[2], archived fromthe original on2 July 2022, page12:
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 elevatorjam 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.
(countable, popular music) An informal,impromptu performance or rehearsal.
(slang) Something enjoyable; a delightful situation or outcome.
1939 July 19,The Bulletin, Sydney, page14, column 1:
’Tis fine to be a pretty girl, or just a gay and witty girl, And obviously to be both is rightly countedjam, But even more desirable, and clearly less acquirable, Is that mysterious quality denominated glam.
The Ship, which by its Building wasSpanish, stuck fast,jaum’d in between two Rocks; all the Stern and Quarter of her was beaten to Pieces with the Sea[…]
They temporarily stopped the gas tank leak byjamming a piece of taffy into the hole.
The rush-hour train wasjammed with commuters.
1779,George Colman, Farewell Epilogue, spoken at Wynnstay after the representation of Cymbeline and The Spanish Barber, 22 January, 1779, inProse on Several Occasions: Accompanied with Some Pieces in Verse, London: T. Cadel, 1787, Volume 3, p. 283,[3]
2019 February 14,National Transportation Safety Board, “2.3.3 Elevator Load Testing”, inAircraft 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[4], archived fromthe original on2 July 2022, page56:
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).
^Meyer,G. (1891) “jam”, inEtymologisches Wörterbuch der albanesischen Sprache [Etymological Dictionary of the Albanian Language] (in German), Strasbourg: Karl J. Trübner,→DOI,pages160–161
^De Vaan, Michiel (2008) “sum”, inEtymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill,→ISBN,page599
Elson, Benjamin F., Gutiérrez G., Donaciano (1999)Diccionario popoluca de la Sierra, Veracruz (Serie de vocabularios y diccionarios indígenas “Mariano Silva y Aceves”;41)[6] (in Spanish),Instituto Lingüístico de Verano, A.C.,→ISBN, page74
The reduced forms with an apostrophe areenclitic; they immediately follow verbs or conjunctions.Dü is deleted altogether in such contexts. Et is not enclitic and can stand in any unstressed position; the full subject formhat is now rarely used. Inreflexive use, only full object forms occur. Dual formswat / unk andjat / junk are obsolete. Attributive and independent possessives are not distinguished in Mooring.
The reduced forms with an apostrophe areenclitic; they immediately follow verbs or conjunctions.Dü is deleted altogether in such contexts.
Et is not enclitic and can stand in any unstressed position; the full subject formhat is now rarely used. Inreflexive use, only full object forms occur.
The dual forms are dated, but not obsolete as in other dialects.
Independent possessives are distinguished from attributive ones only with plural referents.
D. G. Lewis, N. Lewis, editors (2005–present), “jam”, inGweiadur: the Welsh-English Dictionary, Gwerin
R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “jam”, inGeiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies
