What is "keystone"

Keystone \Key"stone`\, n. (Arch.) The central or topmost stone of an arch. This in some styles is made different in size from the other voussoirs, or projects, or is decorated with carving. See Illust. of Arch.

"stone in the middle of an arch, which holds up the others," 1630s, from key (n.1) in figurative sense of "that which holds together other parts" + stone. Figurative sense is from 1640s. Pennsylvania was called the Keystone State because of its position (geographical and political) in the original American confederation, between northern states and southern ones. Keystone cops were the bumbling police in the slapstick silent movies produced by Keystone Company, formed by Canadian-born U.S. film director Mack Sennett (1884-1960) in 1912.

n. 1 (context architecture English) The top stone of an arch. 2 A native or resident of the American state of Pennsylvania.

1. n. a central cohesive source of support and stability; "faith is his anchor"; "the keystone of campaign reform was the ban on soft money"; "he is the linchpin of this firm" [syn: anchor, mainstay, backbone, linchpin, lynchpin]

2. the central building block at the top of an arch or vault [syn: key, headstone]

Keystone may refer to:

• Keystone (architecture), a central stone or other 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
• Keystone (cask), a 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 the Hercules constellation
• Keystone Press Awards
• Keystone (limestone), quarried in the Florida Keys
• Keystone, a variety of screwdriver blade
• Keystone Initiative, a medical protocol to reduce infection rates

The Keystone was a set of eight lightweight streamlined cars built by the Budd Company in 1956 for the Pennsylvania Railroad. The set comprised seven coaches seating a total of 574 passengers and a single head end power (HEP) generator car. The train was normally used in New York, New York, to Washington, D.C., service, making two round trips per day. The design was not a success and the cars were retired in 1968.

Keystone beer is a product of the Molson Coors Brewing Company in Golden, Colorado. It was first introduced in Chico, California in September 1989. Keystone can be found in canned, kegged, and occasionally, bottled form. Keystone Light has a 4.13% ABV; a concentration less than standard American lagers, and roughly equal to other macro "light" brews.

The Keystone was an American automobile manufactured from 1914 until 1915. Designed by Chas C. Snodgrass and built in Pittsburgh, it ran using a Rutenber 55 hp six engine. It was built on a 138 inch wheelbase.

Keystone is the twenty-fifth album by trumpeter Dave Douglas. It was released on the Greenleaf label in 2005 and features performances by Douglas, Jamie Saft, DJ Olive, Gene Lake, Marcus Strickland, and Brad Jones. The music was written to accompany Roscoe 'Fatty' Arbuckle's silent films and a DVD containing the complete film Fatty and Mabel Adrift (1916) and a collage of Arbuckle's scenes set to "Just Another Murder" is included with the album.

A keystone is the wedge-shaped stone piece at the apex of a masonry arch, the generally round one at the apex of a vault. In both cases it is the final piece placed during construction and locks all the stones into position, allowing the arch or vault to bear weight. In both arches and vaults, keystones are often enlarged beyond the structural requirements, and often decorated in some way. Keystones are often placed in the centre of the flat top of openings such as doors and windows, essentially for decorative effect.

Although a masonry arch or vault cannot be self-supporting until the keystone is placed, the keystone experiences the least stress of any of the voussoirs, due to its position at the apex. Old keystones can decay due to vibration, a condition known as bald arch.

In a rib-vaulted ceiling, keystones may mark the intersections of two or more arched ribs. For aesthetic purposes, the keystone is sometimes larger than the other voussoirs, or embellished with a boss. Mannerist architects of the 16th century often designed arches with enlarged and slightly dropped keystones, as in the "church house" entrance portal at Colditz Castle (see image). Numerous examples are found in the work of Sebastiano Serlio, a 16th-century Italian Mannerist architect.

A keystone is a small wooden or plastic fitting used in ale casks.

For some years wooden casks have been effectively obsolete, with the majority now being aluminium or stainless steel, and a few sturdy plastic ones beginning to appear. Nevertheless, the standard tap is still designed to be hammered into yielding material, punching a hole as it goes. All modern casks, even the few wooden ones still in use, use a replaceable keystone to accept the tap.

The bung-hole of the cask is on one of the circular faces, near the rim. When the cask is in service, it is laid on its side with the bunghole at the lowest point on the circumference. The keystone is a small thick wooden or plastic disk inserted into the bunghole which completely seals the cask until it is needed.

The centre of the keystone is deliberately weakened, this area may be marked or unmarked and is called the tut. In the plastic variety it is much thinner than the surrounding material; if made of wood it is partially pre-cut so that it is easier to punch out. Some time before the cask is to be served, the end of the tap is placed against this weakened section and, with the aid of a mallet, driven through it. The shaft of the tap is tapered, so that as it is forced in fully it seals against the undisturbed outer part of the keystone. A small amount of beer may leak out during this process, but with sufficient skill and firm action with the mallet, no spillage at all can occur.

When the cask is empty, it is a courtesy to the drayman (the brewery's delivery driver who also collects the empty casks) to stop up the hole in the keystone with a small cork bung which can be obtained for this purpose. This prevents old beer being spilled on him or in his vehicle. Similarly, the shive hole may be sealed with a spile.

It is common for wooden keystones to acquire a layer of mould on the outside between filling and tapping. This does not indicate a problem with the beer, but because part of the keystone is driven into the cask (where it floats on top of the beer) it must be thoroughly cleaned before the cask is tapped. This action is worthwhile even when plastic keystones are used.

The Keystone Steamer was an American automobile manufactured from 1899 until 1900 in Lebanon, Pennsylvania.

The manufacturer was the Keystone Match & Machine Company, founded in 1894 and offering bicycles from 1896. In 1899 the company offered an interesting but complicated steam car. It featured runabout coachwork and was powered by three small single-cylinder steam engines built into each of its rear wheel hubs in a way that they worked as a radial engine. It was tried to avoid the use of sprockets, chains and a differential gear as each wheel worked completely independent from the other. The vehicle could reach a maximum speed of .

Planned production included also trucks, but the Keystone Match & Machine Co. gave up all automobile projects in 1900, concentrating instead in producing matches and machinery for that purpose.

Engineer J. G. Xander, who mainly developed the Keystone Steamer, went to Reading, Pennsylvania where he manufactured steam and gasoline engines, and offered for a short time the Xander automobile, built on custom order.

The Keystone, also known as Keystone Berkeley, was a small music club in Berkeley, California, which operated in the 1970s and 1980s. Numerous nationally known groups performed there, and the club was a regular venue for the Jerry Garcia Band.

Keystone is a type of limestone, or coral rag, quarried in the Florida Keys, in particular from Windley Key fossil quarry, which is now a State Park of Florida. The limestone is Pleistocene in age, and the rock primarily consists of scleractinian coral, such as Elkhorn coral and Brain coral. The Hurricane Monument, commemorating victims of the Labor Day Hurricane of 1935, and located at mile marker 82 on US Route 1 near Islamorada, is constructed of keystone, as is the David W. Dyer Federal Building and United States Courthouse.