keystone
nounThe central wedge-shaped stone of an arch that locks its parts together.
nounThe central supporting element of a whole.
nounThe 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.
nounHence A supporting principle; the chief element in a system; that upon which the remainder rests or depends.
nounIn 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
In a Scottish 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
nounThe 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
The
A native or resident of the American state of
the central building block at the top of an arch or vault