Etymology The noun is from late Middle English jagge, from Old English giagga, giacga. The ultimate origin could be sound-symbolic of sudden movement, compare with jam, rag and Middle English dag, of which jag may be a palatalised variant. The verb is from jaggen, from Old English giacgian.
1
To cut unevenly.
On the Friday […] we had been playing tennis and in some way Geoffrey jagged a finger nail so that it kept catching in his things whenever he touched it.1934, Ernest Bramah, The Bravo of London:
"One of the ticket collectors at our local station," observed Mr. Fiennes, "has a Jag."1960 February, “The future of B.R. passenger traffic”, in Trains Illustrated, page 76:
jag
noun
Etymology The noun is from late Middle English jagge, from Old English giagga, giacga. The ultimate origin could be sound-symbolic of sudden movement, compare with jam, rag and Middle English dag, of which jag may be a palatalised variant. The verb is from jaggen, from Old English giacgian.
garments thus beset with long jagges and pursles1659, T[itus] Livius [i.e., Livy], “(please specify the book number)”, in Philemon Holland, transl., The Romane Historie […], London: […] W. Hunt, for George Sawbridge, […], →OCLC:
The thick black cloud was cleft, and still / The Moon was at its side; / Like waters shot from some high crag, / The lightning fell with never a jag, / A river steep and wide.1798, Samuel Taylor Coleridge, The Rime of the Ancient Mariner, lines 323–7:
2 more examples
The especial beauty of London is the Thames, and the Thames is so wonderful because the mist is always changing its shapes and colours, always making its light mysterious, and building palaces of cloud out of mere Parliament Houses with their jags and turrets.1909, Arthur Symons, London: A Book of Aspects, self-published, page 3:
Even if you hadn’t been drowned, you would have been smashed to pieces by the terrible weight of water against the countless jags of rock.1956, C. S. Lewis, chapter 16, in The Last Battle, Collins, published 1998:
2
A part broken off; a fragment.
some Jaggs will ſuffice to be recited1693, John Hacket, Scrinia Reserata:
I depart as air .... I shake my white locks at the runway sun, / I effuse my flesh in eddies and drift it in lacy jags.1855, Walt Whitman, “Song of Myself”, in Leaves of Grass, page 56:
3
A flap, a tear in a clothing
4
Biology, Botany, Natural sciences A cleft or division.
Etymology Circa 1597; originally "load of broom or furze", variant of British English dialectal chag (“tree branch; branch of broom or furze”), from Old English ċeacga (“broom, furze”), from Proto-Germanic *kagô (compare dialectal German Kag (“stump, cabbage, stalk”), Swedish dialect kage (“stumps”), Norwegian dialect kage (“low bush”), of unknown origin.
1
Enough liquor to make a person noticeably drunk; a skinful.
2
A binge or period of overindulgence; a spree.
Consider, the pessimists argue, the vast number of plays which it is only possible to sit through with the assistance of what Ella Wheeler Wilcox would call a mild jag.1919 August, P. G. Wodehouse, “Prohibition and the Drama”, in Vanity Fair, page 21:
‘People who spend their money for second-hand sex jags are as nervous as dowagers who can't find the rest-room.’1939, Raymond Chandler, The Big Sleep, New York: Alfred A. Knopf, page 77:
1 more example
He eventually finished the novel after a 10-day writing jag.2026 April 4, Jonathan Derbyshire, “Lunch with the FT: Jay McInerney”, in FT Weekend (Life & Arts section), London: The Financial Times Ltd., →ISSN, →OCLC, page 3:
3
A fit, spell, outburst.
Of course she did not lose her sense of humor (not necessarily to be confused with her laughing fits, which are crying jags turned inside out according to the shrinks).1985, Peter De Vries, chapter 9, in The Prick of Noon, Penguin, page 165:
Miles had a cold, he always had a cold, it went unnoticed, went without saying, he had coughing jags and slightly woozy eyes, completely unremarked by people who knew him […]1997, Don DeLillo, Underworld, Simon & Schuster, published 2007, Part 4, Chapter 1, p. 396:
4
A one-horse cart load, or, in modern times, a truck load, of hay or wood.
5
Scotland, Archaic A leather bag or wallet; (in the plural) saddlebags.