Keystone

Keystone may refer to:

Keystone (architecture), the piece at the apex of an arch or vault
The Keystone effect, caused by projecting an image onto a surface at an angle, or by photography at an angle

Business

Keystone Aircraft Corporation, an early manufacturer of airplanes
Keystone (beer brand), a beer from Coors Brewing Company
Keystone Broadcasting System, an early radio network in the United States
Keystone Camera Company
Keystone (gasoline automobile), an automobile from Pittsburgh
Keystone (steam automobile), a steam car from Lebanon, Pennsylvania
Keystone Shipping Co., an America Ship transport company
Keystone View Company, a US photo agency founded in 1892

Entertainment

Keystone (video game), an Xbox Live Arcade casino gambling game
Keystone Cops, a series of silent movies
Keystone Kapers, a classic Atari game wherein a police officer pursues a thief
Keystone Studios, movie studio
Keystone Entertainment, an independent movie stduio

Places

United States
The "Keystone State", the nickname for the U.S. Commonwealth of Pennsylvania, which has been in use since 1802.
Keystone, California
Keystone, Imperial County, California
Keystone, Los Angeles County, California
Keystone, Tuolumne County, California
Keystone, Colorado, a town
Keystone Resort, the related ski resort
Keystone, Florida, an unincorporated community
Keystone, Indiana
Keystone, Iowa
Keystone, Montana
Keystone, Nebraska
Keystone, South Dakota, a town near Mount Rushmore
Keystone at the Crossing, a business/shopping district located in Indianapolis, Indiana
The Fashion Mall at Keystone, a mall located in the Keystone shopping district
Keystone Heights, Florida, a small city
Keystone lake,resort area near Tulsa ,Ok in rural creek county formed by the meeting of the arkansas river and cimarron river. Bald eagles are frequently seen in the hills surrounding the lake and dam.

Fictional
Keystone City, home of the comic book character the Flash

Railroads

Keystone Service (Amtrak), Amtrak's current New York-Harrisburg
Keystone (Amtrak), Amtrak's former New York-Pittsburgh service
Keystone (PRR), Pennsylvania Railroad's former New York-Washington service
Keystone (train), a lightweight train built for the Pennsylvania Railroad on 1956, by the Budd Company

Schools

Keystone School, a private K-12 school in San Antonio, Texas
Keystone National High School, a private correspondence school

Other uses

Keystone (cask), a wooden or plastic fitting used in ale casks
Keystone module, a type of data connector mounted in walls and patch panels
Keystone species, species that have a larger effect on their environment than is purely due to their abundance
Operation Keystone during World War II
The Keystone asterism in Hercules (constellation)
Keystone Press Awards, given to Pennsylvania reporters
Keystone (limestone), a type of limestone quarried in the Florida Keys
The keystone variety of slotted screwdriver blade
Keystone Initiative, a medical protocol based on a 2003 Michigan study involving intervention at over 100 Intensive care units (ICUs) to successfully reduce infection rates
Keystone pricing, a description of retail pricing whereby the consumer price is exactly double the wholesale price

Translation

The word "Keystone" occurs as such in the following languages: English, German, Dutch, Polish, Portuguese, Volapük.