Gyro

"Gyro" is the Greek version of New York's Italian "hero" sandwich. I've traced the "gyro" citational origins to the 1960s and the Parthenon Restaurant in Chicago.

"Gyro" exploded onto the New York City scene in the early 1970s. In other parts of the world it is called a "YEE-roh." In New York City, most call it a "JY-roh."


Wikipedia: Gyros
Gyros or gyro (giros) (most often pronounced /ˈdʒaɪroʊ/, from Greek: γύρος "turn") is a Greek dish, consisting of meat, tomato, onion, and tzatziki sauce, and is served with pita bread. Gyros may also refer to the sandwich, which consists of the same ingredients.

The Middle Eastern shawarma and Mexican tacos al pastor are similar to gyros, and all derived from the Turkish döner kebab which was invented in Bursa in the 19th century.

To make gyros, slices of meat are placed on a tall vertical spit, which turns in front of a source of heat. The rate of roasting can be adjusted by varying the strength of the heat and the distance between the heat and the meat, allowing the cook to adjust to varying rates of consumption. The meat is sliced vertically. It is generally served in an oiled, fried piece of pita, rolled up with various salads and sauces.

Gyros served in the United States usually use a processed meat, because of sanitary regulations against raw lamb storage.
(...)
United States
Gyros were introduced to Chicago in 1968, and have since spread to all parts of the country. In the United States, gyros is usually made from lamb or a combination of beef and lamb. Chicken may also be used as an ingredient.

The name gyros is most commonly used in American and Greek-American restaurants and stores. Doner kebab and shawarma may be seen in Middle Eastern-style establishments.

The bread served with gyros in the U.S. resembles a Greek 'plain' pita. The most common accompaniments are tomato and onion and tzatziki, sometimes called "cucumber", "yogurt", or "white" sauce. These sandwiches are often served in luncheonettes or diners.

While many Greek restaurants in America make gyros in a traditional way from sliced meat arranged on a vertical rotisserie, others, particularly fast-food restaurants, use prefabricated gyros loaves, made of ground meat pressed into a cylinder and cooked on a rotating vertical spit, from which thin slices of meat are sliced as they brown.

Many restaurants (and even Greek-American festivals) sell gyros which is pre-formed into strips (as though they had been sliced from the rotisserie) and frozen to meet USDA health standards. Some establishments, serving varied menus, choose to grill or pan fry individual strips of the gyros meat to prevent waste.

Devanco Foods
THE HISTORY OF GYROS
Among the many Greek delicacies that exist, the most prestigious of them all is a product commonly known as "GYROS". Gyros has been a part of the traditional Greek cuisine for hundreds, if not thousands, of years. Although its true origin is unknown, its initial impact and influence on the American Food Industry can be attributed to the pioneering efforts of one individual affectionately known as "Papa George". George Apostolou is the father of the Gyros dish that is loved and enjoyed by many in restaurants across North America. He was the first person to successfully manufacture, promote and market Gyros. Today, thousands of restaurant owners across the country make a living by serving Gyros.

George first introduced Gyros to the American public in 1965 at The Parkview Restaurant, a small establishment that he owned with his cousins in Chicago, Illinois. Customers enjoyed the new Gyros product, although some were intimidated by its awkward appearance. The Gyros craze was just beginning and Papa George was about to make a big impact on the food industry. Restaurant owners saw this potential and inquired as to how they could offer Gyros because customers were looking for an alternative to hamburgers.

Merriam-Webster Online Dictionary
Main Entry: 2gy·ro
Pronunciation: \ˈyē-ˌrō, ˈzhir-ō\
Function: noun
Inflected Form(s): plural gyros
Etymology: Modern Greek gyros turn, from Greek; from the rotation of the meat on a spit
Date: 1971
: a sandwich especially of lamb and beef, tomato, onion, and yogurt sauce on pita bread

(Oxford English Dictionary)
gyro
A sandwich made with pitta bread and containing slices of cooked spiced meat (usu. lamb or beef), tomatoes, onions, etc. Cf. DONER KEBAB n.
1971 N.Y. Times 4 Sept. 23/1 More than 30 Greek snack stores selling the gyro have opened in Manhattan in the last year.
1978 New Yorker 23 Oct. 101/1 Soyer circled the area, took his time, and settled for a Greek gyromounds of thinly sliced, garlicky pressed beef and lamb on pita bread.

December 1968, WFMY Guide (Chicago, IL) pg. 40, col. 2:
THE PARTHENON--314 S. Halsted. Greek. A good deal of seafood (including squid and octopus), over a dozen lamb dishes including gyros, spit-roasted slices of beef and lamb with onion and parsley. The usual Greek wines and liquors plus beer by glass and pitcher. Large room with efficient service. Greek music on records. Daily 11-2 am. Child. 726-2407.

11 April 1969, Chicago (IL) Tribune, "Front Views & Profiles: The New Parthenon" by Kay Loring, sec. 1A, pg. 8, col. 4:
The octopus [cold], the moussaka, and the gyros [barbecued lamb turning on a spit in the window while we were there] were all quite special; ...

19 June 1970, Chicago (IL) Tribune, "Eating Out: A 'Greek letter' crew" by John R. Thomson, sec. 2, pg. 16, col. 2:
Logan ordered gyros [barbecued lamb and beef] at $1.95, ...
(At the Parthenon Restaurant, 314 S. Halsted St. -- ed.)

7 August 1970, Chicago (IL) Tribune, "The makings of a picnique with an international flavor" by Mary Daniels, sec. 2, pg. 1, col. 3:
SURELY "ZORBA" would approve a picnic prepared at the Parthenon Restaurant, 314 S. Halsted St., in Greektown. Start with cold octopus in an herbed, oily dressing [the dish is put in a cardboard "boat" and wrapped with tinfoil 90 per cent leak-proof], follow with "gyros," which is lamb and beef layered in alternate slabs, herbed, garlicked, basted and rotisseried slowly. Accompany with a large bottle, from the bar, of tart rotidis wine. Ass some sesame-sprinkled bread. All for about $9 per gluttonous couple.

11 October 1970, The Courier-Journal (Louisville, KY), "Treats from the Sandwich Board" by Joan Bowser, Tuesday magazine, pg. 30, col. 3:
Greek Gyros
This sandwich calls for an unleavened flat bread that is bigger than a roll and thin, similar to Syrian bread. The bread is warmed on the grill with a little olive oil. It is stuffed with thin slices of barbecued lamb, chopped raw onions, parsley, oregano and green pepper.

27 May 1971, Chicago (IL) Tribune, section 2, pg. 19:
This Parthenon, Too, Is Classic Greek
(...)(Col. 2 -- ed.)
Next came gyros ($1.95 a plate), unusual, intriguing and thoroly (sic) Greek. It consists of layers of specially spiced lamb and beef, barbecued vertically on equipment imported from Greece, which is set up in the window at the front of the restaurant.
(Photo caption, col. 6 -- ed.)
Bill Liakouras slices a dishful of gyros, vertically barbecued layers of spiced lamb and beef.

Google Books
The Food of Greece
By Vilma Liacouras Chantiles
New York, NY: Atheneum
1975
Pg. 155:
GYRO
[Spitted spiced lamb]
Gyro, gyro oli is a favorite children's game, comparable to farmer in the dell, which describes the round-and-round motion of gyro. Since spreading to Greece from the Middle East, industrious Hellenes have brought it to the United States (New York is spinning with gyro restaurants), and one more snack has been added. On a vertical spit, which turns electrically, or is run manually by the mikro (apprentice), the meat is roasted to flavorful crispness. I adapted this recipe from a tasty snack in Crete. To make at home, grill outdoors (horizontally when lacking a vertical grill), and indoors, broil -- delicious. (Recipe follows -- ed.)

New York (NY) Times
The Gyro’s History Unfolds
By DAVID SEGAL
Published: July 14, 2009
Chicago.
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The question is: Who is the Henry Ford of the gyro? It turns out there are a handful of contenders, all of whom know one another and have been friendly competitors for decades. They include George Apostolou, who says he served the first gyros in the United States, in the Parkview Restaurant in Chicago, in 1965, and nine years later opened a 3,000-square-foot manufacturing plant, Central Gyros Wholesale.

“The response to the product was tremendous,” Mr. Apostolou said. “My two brothers and I, we became millionaires in two years’ time.”