What alphabet of lines what line type can be used on a drawing to represent the area in which the gear teeth exist although the gear teeth are not drawn?

The alphabet of lines that can be used to represent the area in which the gear teeth exist, even if the teeth are not drawn, is a phantom line. Phantom lines are typically represented by alternating long and short dashes and are used to indicate the outlines of objects that are not currently visible or are omitted for clarity. In the context of gears, this allows for the representation of the gear's overall space without detailing every tooth.