Contour

Illustration: Words of Type. Typeface in use: Knowledge Rounded, designed by Lisa Huang, 2024.
Also called Outline.
The shape of a glyph is defined by one or more contours. In digital typeface design, the contour is what the designer draws. What the user sees on screen or in print is the filled shape in between these contours.
Contours and outlines are related but not exactly the same. An outline is the full outer shape of a glyph: it defines what the glyph looks like overall. While a contour is one continuous closed path within that outline. For example, the outline of the letter O typically has two contours; one for the outer circle and one for the inner counter (the transparent “hole”).