Eponym refers to a person, real or imaginary, after whom something has been named, as well as to the name itself. Eponyms are found in many different branches of knowledge, industry, and enterprise. It is not unusual to find eponyms used for company names, places, discoveries, honors, and inventions. One can also find eponymous products, anatomical entities, ideologies, foods, and other items that recall someone by their name. An eponym is distinguished from a toponym, which is a name derived from a place or region, like tangerine, a fruit named for Tangiers, Morocco.

Cuisine Eponyms. The Granny Smith apple, like many botanical species, is named for its New South Wales discoverer and grower. Foods may be named for their inventor, as Graham flour, named after its inventor Rev. Sylvester Graham, and prepared dishes may be named after the person they were created for or after the chef who created them. Peach Melba, prepared by the chef Auguste Escoffier for Australian opera singer Dame Nellie Melba, was named after the woman who inspired it, while Sachertorte, a chocolate cake created by baker Franz Sacher for Klemens Wenzel von Metternich, was named for the chef, not the patron.

Music Eponyms. The Sousaphone is named after its inventor, composer and conductor, John Philip Sousa. The Tourte bow for string instruments bears the name of its inventor, French bow-maker François Xavier Tourte. The Landini cadence was named after Italian composer and organist Francesco Landini. The Bartok and the Verdi scales were named after composers Bela Bartok and Guiseppe Verdi.

A set of chord changes – Coltrane changes – is named after the innovative jazz saxophonist and composer who came up with them, John Coltrane. The music notation software application, Sibelius, bears the name of composer Jean Sibelius. A special meaning of eponym, specific to the music industry, is an album that takes its title from the name of the recording artist(s) or one of its tracks.

Science Eponyms. Eponymous names have been given to elements, like Einsteinium named after physicist Albert Einstein; planets, like minor planet (3834) Zappafrank, named after rock musician and composer Frank Zappa; animals, like the spider named Mastophora dizzydeani after the Major League pitcher, Dizzy Dean; laws, theorems, and principles, such as Ampère’s law, named after French physicist André-Marie Ampère; units and constants such as Avogadro’s number or constant, named after Amedeo Avogadro, an Italian chemist; diseases, such as Hodgkin’s lymphoma, named after the man who described it, Thomas Hodgkin; anatomical structures, such as the Adam’s apple, named after the first man; and tests, such as the Rorschach inkblot test, developed by Swiss psychiatrist Hermann Rorschach.

Time Eponyms. Some of our days of the week, like Wednesday - named for the Norse God Odin - are eponymous. We also have months named after Roman gods and emperors – January for Janus, the god of beginnings, and July and August for emperors Julius and Augustus Caesar. The Julian and Gregorian calendars – the first introduced by Julius Caesar, the second named after Pope Gregory XIII who decreed its use – are further examples.

Place Eponyms. Islands, states, countries, towns and cities, and bodies of water have all been named after people. Saint Kitts and Nevis was named after Saint Christopher. Pennsylvania was named after its founder's father, Admiral Sir William Penn. Bolivia was named for the South American revolutionary, Simón Bolívar. Seattle, Washington was named for Chief Seattle, leader of the Suquamish and Duwamish tribes. The Hudson River was named for English explorer Henry Hudson.

Airport, Dam, Park, Road, and Bridge Eponyms. O’Hare Airport in Chicago is named for Edward “Butch” O’Hare, a World War II medal-winning aviator. The Hoover Dam was named for President Herbert Hoover, and Governor Tom McCall Waterfront Park in Portland, Oregon, is named after a former governor of the state. Boulevard Jacques-Cartier in Longueueil, Quebec is named for French explorer Jacques Cartier. The Arthur Fiedler Footbridge in Boston, Massachusetts is named after conductor Arthur Fiedler, long time leader of the Boston Pops Orchestra.

Toy, Company, Vehicle, Sports, and Clothing Eponyms. There are many more eponymous items, too many to recount, but here are a few. The Teddy bear is named after President Theodore Roosevelt. The Ford Motor Company and the cars it makes are named after inventor Henry Ford. The Fosbury flop, a method for high jumping, is named after its inventor, Dick Fosbury. Finally, the Stetson hat is named after John B. Stetson, the hat maker, and there is a Stetson Fedora – named after the play Fedora by Sardou, which has an eponymous title, as the play was named after the heroine – named the Temple/Indiana Fedora after the movie character Indiana Jones – that may be the most layers of eponym involved in one item!