The standard shade measurements are:
1. top diameter2. bottom diameter3. slant, down the side of the lampshade.
The measurements on our shades are taken in that order.
Drops: Some shades have a drop. The drop is the distance from the shade's clip to the top of the lamp shade. A shade with no drop has the clip at the top of the lamp shade (no distance between the top of the shade and the clip.)