levelein
Levelein is a term found in Dutch-language technical texts that denotes a line on a plan or map representing a constant vertical position or grade. It is conceptually similar to an elevation line or contour line, but it is not a standardized term and may appear in regional, project-specific, or older sources. The exact definition can vary by field.
In surveying, civil engineering, and architecture, a levelein serves as a reference for establishing horizontal alignment
Because levelein lacks universal standardization, practitioners often substitute more common terms or specify its meaning within