What does "drop" mean in jacket sizing?

Drop is the difference in inches between a jacket’s chest and waist measurements — a "6-drop" jacket has a waist six inches smaller than the chest, a "7-drop" runs slimmer and more tapered, and lower drops are boxier. It decides whether an off-the-rack jacket suits your build before any tailoring: an athletic V-shape wants a higher drop, a straighter build a lower one. Most brands publish one drop across all sizes, which flatters some bodies more than others. Knowing your own chest-to-waist difference and a jacket’s drop predicts fit — and whether the waist will need taking in — far better than the size label alone.