The amount of fabric that needs to be folded or cut out to shape the dart.
The larger the intake, the wider the dart, the more curved the mound. This means that for shaping the bust, the larger the bust-cup, the larger the dart intake. For shaping from the hips to the waist, the larger the measurement difference between the hips/waist, the larger the dart.
The dart intake is the value of the width between the dart legs.
In this image, Size 12 B-cup, C-cup & D-cup are shown. The value of the side seam dart increases with each bust-cup increase.
The side seam dart value from the B-cup (red shaded area) has been copied onto the C-cup and the D-cup blocks so you can see the comparative increase in the dart values.
(Note: Although the side seam length may seem to increase, it is actually the same for these three blocks; the seeming increase is due to the side seam dart value increase. The Centre Front length, however, has increased. The waist darts values are the same for all three).