This page deals with slang terms for a Zombie apocalypse, in the heat of the moment it's easy to garble in horror at the situation and important messages are lost so easy terms are introduced by the military which are inevitably adopted and mutated by civilians.
In art, an underpainting is an initial layer of paint applied to a ground, which serves as a base for subsequent layers of paint. Underpaintings are often monochromatic and help to define colour values for later painting.
In manufacturing, an undercut is a special type of recessed surface. In turning it refers to a recess in a diameter. In machining it refers to a recess in a corner.n machining the corners may be undercut to remove the radius that is usually left by the milling cutter. Examples of this use are linear bearings for square shafts (i.e. racks) and machined hexalobular sockets.