The bounding box is a virtual rectangle enclosing a selected (vector) shape—such as a segment, an outline, or an entire glyph.

The font bounding box defines the outermost limits of a typeface, marked by the four extreme coordinates along the X and Y axes: highest (Y-max), lowest (Y-min), leftmost (X-min), and rightmost (X-max).

FONT ENGINEERING ADVICE

The font bounding box is stored in the head table.