Keystone or key-stone may refer to: *

Keystone (architecture) A keystone (or capstone) is the wedge-shaped stone at the apex (geometry), apex of a masonry arch or typically round-shaped one at the apex of a Vault (architecture), vault. In both cases it is the final piece placed during construction and l ...

, a central stone or other piece at the apex of an arch or vault * Keystone (cask), a fitting used in ale casks

Companies

* Keystone Law, a full-service law firm * Digital Keystone, a developer of digital entertainment software *

Keystone Aircraft Keystone Aircraft Corporation was an early American airplane manufacturer. History Headquartered in Bristol, Pennsylvania, the company was formed as "Ogdensburg Aeroway Corp" in 1920 by Thomas Huff and Elliot Daland, but its name was quickly c ...

Corporation * Keystone Bridge Company, an American bridge building company * Keystone (beer brand) * Keystone Camera Company * Keystone (gasoline automobile) * Keystone (steam automobile) *

Keystone Pipeline The Keystone Pipeline System is an Pipeline transport, oil pipeline system in Canada and the United States, commissioned in 2010, formerly owned by TC Energy. It is now owned by South Bow, following TC Energy's spin off of its liquids business i ...

, a crude oil pipeline * Keystone-SDA/Keystone-ATS, a Swiss press agency * Keystone View Company, a US photo agency * Keystone (Berkeley, California), a defunct music club

Education

* Keystone Academy, a private K–12 school in Shunyi, Beijing, China * Keystone College, a private college in Pennsylvania, United States * Keystone Exam, a standardized test at public schools in Pennsylvania, United States * Keystone School, a private K–12 school in San Antonio, Texas, United States * Keystone School Online, a private for-profit online K–12 school based in Herndon, Virginia, United States * Keystone, an education program at the U.S.

National Defense University National Defence (or Defense) University (or College) may refer to: :''Alphabetical by country'' University * Marshal Fahim National Defense University, Afghanistan * National Defense University (Azerbaijan) * People's Liberation Army National Defe ...

Entertainment

* ''Keystone'' (video game), part of the Xbox Live Arcade title ''Fable 2 Pub Games'' * Keystone (band), led by jazz trumpeter Dave Douglas ** ''Keystone'' (album), a 2005 album by the band * Keystone Cops, a silent movie series * '' Keystone Kapers'', a classic Atari game * Keystone Studios, a movie studio

Places

* The Keystone asterism in the Hercules constellation

United States

* The "Keystone State", nickname for the U.S. Commonwealth of

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

* Keystone, Colorado, a town ** Keystone Resort, the related ski resort * Keystone, Florida, an unincorporated community * Keystone, Indiana * Keystone, Iowa * Keystone, Missouri * Keystone, Nebraska * Keystone, North Dakota * Keystone, Ohio * Keystone, South Dakota, a town near Mount Rushmore * Keystone, Washington, an unincorporated community * Keystone, West Virginia * Keystone, Wyoming * Keystone at the Crossing, a business/shopping district in Indianapolis, Indiana ** The Fashion Mall at Keystone, located in the Keystone shopping district * Keystone Heights, Florida * Keystone Canyon, Alaska * Keystone Lake, a resort area near Tulsa, Oklahoma * Keystone, Wisconsin

Canada

* The "Keystone Province", a nickname for the Province of Manitoba ** Keystone Centre, an arena and exhibition centre in Brandon, Manitoba

Fictional locations

* Keystone City, home of the comic book character The Flash * Keystone City, a holographic city in the ''Star Trek: The Next Generation'' episode "

Emergence In philosophy, systems theory, science, and art, emergence occurs when a complex entity has properties or behaviors that its parts do not have on their own, and emerge only when they interact in a wider whole. Emergence plays a central rol ...

Railroads

* Keystone Corridor, a rail corridor from Philadelphia to Pittsburgh * '' Keystone Service'', a current New York-Harrisburg service ** ''Keystone'' (Amtrak train, 1979–1981), a predecessor of the current service * ''Keystone'' (Amtrak train, 1971–1972), a former New York-Pittsburgh service operated by Amtrak * ''Keystone'', a former New York-Washington service operated by the Pennsylvania Railroad ** ''Keystone'' (train), a lightweight train used for the service

Sports

* Keystone Junior Hockey League, in Manitoba * Keystone Cup, Western Canadian Junior "B" ice hockey championship * Keystone (horse), a racehorse

Other uses

* Keystone (limestone), quarried in the Florida Keys * Keystone effect, caused by projecting an image onto a surface at an angle, or by photography at an angle * Keystone Initiative, a medical protocol to reduce infection rates * Keystone module, a type of data connector mounted in walls and patch panels * Keystone Press Awards * Keystone species, species that have a larger effect on their environment than is purely due to their abundance * Operation Keystone, during World War II * Keystone, a variety of screwdriver blade * "Keystone", a descriptive reference to the Book of Mormon *''The Keystone'', journal of the Pennsylvania Railroad Technical and Historical Society *''The Keystone'', Pennsylvania news website owned by Courier Newsroom