- the central, topmost voussoir of an arch, popularly thought of as especially holding the others in place
- that one of a number of associated parts or things that supports or holds together the others; main part or principle
designating, of, or like the slapstick comedy of a series of silent films featuring a bungling, inept squad of policemen (Keystone Kops or Keystone Cops) in wild chases, etc.
Origin of Keystoneafter Keystone Comedy Co., the film producers
- Architecture A wedge-shaped stone at the top of an arch, often larger or more ornamented than the other voussoirs. Also called headstone .
- The central supporting element of a whole.
- This doctrine of the moral sense is sometimes represented as Shaftesbury's cardinal tenet; but though characteristic and important, it is not really necessary to his main argument; it is the crown rather than the keystone of his ethical structure.
- To the epistemologist it seemed to confuse foundation and keystone, and to suppose itself to build upon the latter in a construction illegitimately appropriative of materials otherwise accumulated.
- Though common sense will admit that virtues are the best of goods, it still undoubtedly conceives practical wisdom as chiefly exercised in providing those inferior goods which Aristotle, after recognizing the need or use of them for the realization of human well-being, has dropped out of sight; and the result is that, in trying to make clear his conception of practical wisdom, we find ourselves fluctuating continually between the common notion, which he does not distinctly reject, and the notion required as the keystone of his ethical system.
- The additional qualification of " Roman " she tolerates, since it proclaims her doctrine of the see of Rome as the keystone of Catholicism; but to herself she is "the Catholic Church," and her members are "Catholics."
- The arch is surmounted by a triple attic with Corinthian columns; the frieze above the keystone bears, on the north-western side, the inscription aZS' 'Aqvat, OouEw 7rpiv rats, and on the south-eastern, aZS' do' `ASptavoii Kai ou X i Ono-Los 'TO Xis.