In Latin script, we speak of a “diagonal,” “tilted” or “oblique” axis when we refer to the shapes of letters in a typeface that have some contrast.

In calligraphy (when using a broad nib pen), the axis of the stroke is defined by the angle at which the pen is held, from which a contrast between thin and thick parts is formed. The axis should be kept the same (or very similar) for a consistent construction on all glyphs.