Architecture The central wedge-shaped stone of an arch that locks its components collectively. Also called headstone.
The central supporting part of a whole.
the most truly effective stone of an arch.
A native or citizen of this American condition of Pennsylvania.
The main or topmost stone of an arch. This in certain styles is manufactured various in proportions from the various other voussoirs, or tasks, or is decorated with carving. See Illust. of arch.
The rock of an arch (typically the uppermost stone), which, becoming the past added, is undoubtedly keying or securing the whole construction collectively; the rock on apex of an arch.
Hence A supporting concept; the principle aspect in a method; that where the rest rests or depends.
In chromolithography, initial rock upon which the image is drawn or photographed, to act as an outline guide in preparing another stones for the colors, a duplicate for the keystone being made for each rock for printing a single color. See lithography.
In a Scotch lead-smelting furnace, a block of cast-iron accustomed close up the room at each end regarding the forestone, and fill-up the room amongst the forestone while the straight back area of the furnace
the main building block at the top of an arch or vault
a central cohesive way to obtain assistance and stability