Scale
Relationship between distance on a map, chart or plan and the corresponding real distance on the Earth
Self-cover
Stiff sections glued to sections of a folding map. When the map is folded properly, the covers protect the map.
Show-through
The image on one side of sheet of paper visible from the other side, through the paper.
Slipcase
An outer case, either box or envelope-like, into which a folded map can be inserted for protection.
State
Each significant alteration to a printing plate created another state of the image.
Steelplate
Engraved on steel rather than copper. Sometimes a copperplate that has been iron-plated is called steelplate. Unlike the earlier woodcuts, additions could easily be made to a plate by simply hammering the plate from the back, smoothing the surface and re-engraving to add the necessary detail.
Steelplates were first used around 1820 and lasted until about 1870, when the method was replaced gradually by lithography.
Stitch holes
Small holes in the centrefold made where the map was sewn into the book or atlas. To avoid stitch holes, many binders attached binder's guards to the map and sewed through these
