• WordNet 3.6
    • n keystone the central building block at the top of an arch or vault
    • n keystone 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"
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Webster's Revised Unabridged Dictionary
    • n Keystone (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.
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Century Dictionary and Cyclopedia
    • n keystone The stone of an arch (typically the uppermost stone), which, being the last put in, is regarded as keying or locking the whole structure together; the stone at the apex of an arch. in Roman and Renaissance arches the keystone is very commonly sculptured as a decorative feature. In groined medieval vaults the keystone at the intersection of the ribs at the summit of the vault is usually ornamented with a sculptured boss or pendant. In a true or extradosed arch no one of the voussoirs is more important to the stability of the structure than any other. See arch, n., 2.
    • n keystone Hence A supporting principle; the chief element in a system; that upon which the remainder rests or depends.
    • n keystone In chromolithography, the first stone on which the picture is drawn or photographed, to serve as an outline guide in preparing the other stones for the colors, a copy of the keystone being made on each stone for printing a single color. See lithography.
    • n keystone In a Scotch lead-smelting furnace, a block of cast-iron used to close up the space at each end of the forestone, and to fill up the space between the forestone and the back part of the furnace
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Chambers's Twentieth Century Dictionary
    • Keystone the stone at the apex of an arch: the chief element in any system
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  • Charles Dickens
    “Industry is the soul of business and the keystone of prosperity.”


Chambers's Twentieth Century Dictionary
A.S. cæg, a key.


In literature:

Keystone door in Campo St. M. Formosa.
"The Stones of Venice, Volume III (of 3)" by John Ruskin
Over the keystone of the central arch there used to be the royal arms.
"Old and New London" by Walter Thornbury
That's the keystone of our friendship.
"John March, Southerner" by George W. Cable
The ornamentally ribbed vaulting with gilt bosses and keystones is carried by clustered shafts engaged in its side walls.
"Cathedrals of Spain" by John A. (John Allyne) Gade
St. Cyr at the moment looked like a Keystone Kop after the chase sequence, and knew it.
"The Ego Machine" by Henry Kuttner
Pennsylvania, the Keystone State.
"The Scrap Book, Volume 1, No. 4" by Various
This examination is the keystone of the whole system.
"Seven Graded Sunday Schools" by Various
She is the keystone of the arch, not the mudsill.
"Oriental Women" by Edward Bagby Pollard
Kant then proceeds to introduce what he evidently considers the keystone of his system, viz.
"Kant's Theory of Knowledge" by Harold Arthur Prichard
He resigned Keyston, and his preachership in Lincoln's Inn (Feb., 1622).
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 6" by Various

In poetry:

Four, and a keystone;
Four, and a keystone;
Four, and a keystone;
Then twenty-four, and a tiny little keystone.
"Tortoise Shell" by D H Lawrence
I am the pillars of the house;
The keystone of the arch am I.
Take me away, and roof and wall
Would fall to ruin me utterly.
"Any Woman" by Katharine Tynan
"But Time with still and stealthy stride,
That climbs and treads and levels all,
That bids the loosening keystone slide,
And topples down the crumbling wall,--
"The Broken Circle" by Oliver Wendell Holmes
Emblem and legend may fade from the portal,
Keystone may crumble and pillar may fall;
They were the builders whose work is immortal,
Crowned with the dome that is over us all!
"Hymn For The Celebration At The Laying Of The Cornerstone Of Harvard Memorial Hall, Cambridge, Octob" by Oliver Wendell Holmes
No never! By that outrage black, A solemn oath we swore,
To bring the Keystone's thousands back,
Strike down the dastards who attack,
And leave a red and fiery track Through Baltimore!
"Through Baltimore" by James Bayard Taylor

In news:

Republican Sen Hoeven helps lead bipartisan effort asking Obama to OK Keystone.
Republican Sen John Hoeven on Saturday urged President Obama to end his election rhetoric and fulfill of the will of the American people by approving the Keystone XL oil pipeline.
AP Photo/Keystone, Dominic Favre, File.
The 40th Street Bridge over AMTRAK Keystone Corridor lines in West Philadelphia, which was rebuilt over the last two years, reopened Saturday a month ahead of schedule.
This is why we need the Keystone pipeline -- more energy and jobs.
Some of the policies he mentioned were pretty conventional for someone of his party: limiting regulations, approving the Keystone XL Pipeline.
A smoky fire near the Keystone switching station closed Route 22 for a short time Sunday.
The Oil Spill in the Yellowstone River & the Proposed Keystone XL Pipeline.
Chemical leak causes issue near Keystone Drive in Coffee County.
A temporary restraining order was issued Friday against the protestors of the TransCanada Keystone Pipeline and groups the protestors represent.
Keystone: Legacy Camp gives kids a framework for dealing with loss, by Jessica Smith, Nov 20.
Obama Delays Keystone XL Pipeline.
Days after State Department officials agreed to reexamine their own report on the Keystone XL oil pipeline, the Obama administration announced this afternoon a 12-to-18-month delay on the deadline for the pipeline's approval.
Review Photo / Amanda Renko Gary Burcher, managing partner of Keystone Consulting, refers to a plan for the proposed Sayre Health Care Center skilled nursing facility and personal care home during a conditional use hearing Monday.

In science:

In this section, we introduce a general construction that turns out to be a keystone for our work.
$K_0$ of purely infinite simple regular rings
The case q < 1 The FKG inequality, a keystone of many arguments when q ≥ 1, is not valid when q < 1.
The Random-Cluster Model
Indeed, the electron pairing is the keystone of superconductivity.
Route to Room-Temperature Superconductivity from a Practical Point of View
The analysis of these atypical RWs, and how they lead to errors is the keystone of what follows.
Reconstructing a Random Potential from its Random Walks
Now we will formulate a technical result which is the keystone in the proof of Theorems 4 and 5.
Equations and fully residually free groups