In The Sopranos's episode “Commendatori”, Tony Soprano and his friends take a business trip to Naples in order to conduct an important deal. In the hotel restaurant, Paulie Gualtieri is served a plate of spaghetti with squid ink. Although he is Italian by origin, Paulie was born in New Jersey and he looks at the dish in semi-disgust. He asks the Italian waiter to bring him some “macaroni and gravy”. The Neapolitan waiter, bewildered, asks the mobster what gravy means, whereby Paulie explains:
Paulie : Gravy, gravy. Tomato sauce!
A camorrista translates it as “pommarola” to the waiter. Here's the video clip of the scene on Youtube.
This isn't the first time I've heard American movies or TV series use the term gravy for the Italianissimo pommarola. But I've never heard it being used in the UK, and I come from a Ligurian family who immigrated to England soon after the second world war. For the Brits, gravy is synonymous with Bisto, OXO and Sunday roast beef. No Englishman or woman would possibly confuse gravy with tomato sauce—gravy is a British institution—and although the art of making gravy from scratch is sadly dying, no Christmas dinner would be complete without it.
So why do Italian-American families call pommarola gravy?
Firstly, pommarola (tomato sauce) is never made with meat, but only from fresh tomatoes with a few torn basil leaves chucked in at the end. Secondly, the meat sauces which Mr. Shiny and New 安宇 mentions in his answer is an ambiguous term. A meat sauce (salsa di carne) can also be a thin sauce that coats the meat or complements any meat dish. However, the thick meaty sauces for spaghetti and macaroni are called ragù; ragù alla bolognese or sugo di carne.
It seems probable to me that the first Italian immigrants in America translated ragù or sugo as “meat sauce” which the Americans interpreted it as being something like gravy.
Apparently, the term stuck and is still used today by italoamericani in New Jersey to mean plain tomato sauce. However, for most Americans and for all Brits, gravy refers to the sauce made from the fat and juices left over in the roasting pan.
EDIT
For many Italian Americans living in New Jersey, it seems gravy is the Italian “pommarola”
For a Former Pizzeria Owner, It’s All Gravy
Last week, we published a case study about a New Jersey pizzeria owner who recently debated two different paths in the food industry: Should he enlarge his tiny restaurant to boost stagnant revenues? Or should he sell the business and start another one to manufacture his restaurant’s red sauce, which he had been selling over the counter as Jersey Italian Gravy?
[background information on the owner, Carlos Vega, and his enterprise]
Q. It’s called Jersey Italian Gravy, but you’re making it in New York?
A. The product evolved in New Jersey. We’re from New Jersey. It’s still a local product. It’s made 60 miles from where we are. Our customers ask us all the time, “Do you use Jersey tomatoes?” We say we used to, but they’re inconsistent. One crop is too sweet, one is too bitter, one is too seedy. So we switched to a California tomato.
Q. Several readers questioned the high retail price of your sauce, $8.99 a jar.
A. […]. Ours is a slow-simmered, small batch, hybrid grocery/specialty product with only five ingredients, and our tomatoes are as expensive as those certified DOP San Marzano.
From The New York Times, January 7, 2014
Chambers Dictionary 11th Ed.:
ORIGIN: Poss *do*llars and ca*sh*
Partridge Dictionary of Slang:
Possibly a combination of dollars and cash; there are also suggestions that the etymology leads back to doss (temporary accommodation), hence, it has been claimed, the money required to doss, or Scottish dialect doss (tobacco pouch, a purse containing something of value) – note, too, that tobacco is related to money via quid. US dosh didn’t survive but in mid-C20 UK and Australia the word was resurrected, or coincidentally recoined US, 1854
Oxford Advanced Learner’s Dictionary 8th Ed.:
1950s: of unknown origin
Oxford English Dictionary:
Origin unknown.
1953 H. Clevely Public Enemy xviii. 114 He hadn't enough dosh on him.
Best Answer
The word 'jippo', in the variant 'jipper', considerably predates slang use (variant 'jippo') in the RAF or World War era army. OED (paywalled) attests use in print as a transitive verb as early as 1822, in Sir Walter Scott's The Fortunes of Nigel (emphasis mine; in context, the use is as nautical slang):
The provenance of the term becomes muddled in later years. OED attests the noun variant 'jippo' from 1929, equating it with the noun variant 'gippo', attested from 1914 and described as "slang (chiefly Services' slang)". OED gives the noun variant 'jipper' (and 'jippo') as the etymology of 'gippo'. The earliest attestation of those noun variants is for 'jipper', in 1886, when it appears in William Henry Long's A dictionary of the Isle of Wight dialect:
A note in Notes and queries v.101, 1900, however, avers use of the noun variant in the sense of "gravy" around 1870:
The sense of "gravy", and ascription to a nautical origin also appears in John S. Farmer and W.E. Henley, Slang and its analogues, 1896:
Earlier appearances of 'jippo' in print, in 1764 and 1806, must be regarded as semantically distinct from later uses of the noun variants 'jipper', 'gippo' and 'jippo' in the sense of "gravy" that developed after Scott's 1822 use of 'to jipper' in the sense of "to baste".
For example, in N. Bailey's 1764 An Universal Etymological English Dictionary, this definition appears:
And in James Leslie's 1806 Dictionary of the Synonymous Words and Technical Terms in the English Language, 'jippo' appears as a synonym of the attributive 'shabby':