Location of the apex of the bust.
The Bust Point on a Block is the pivot point for moving the dart, and should not be confused with the Dart Point.
Showing the Bust Point and the two Dart Points on the Bodice Block Front.
In this example on a garment, the green overlay line (not part of the top) is from Bust Point to Bust Point.
Note that the darts do not go all the way to the Bust Points. (As you can also see in the image of the block above). This is the case for both the side seam and waist darts.