Body measurements, not garment measurements. The measurements shown are body measurements, not garment measurements — they indicate the body size that fits within each size. Measure your bust and hips at their widest point, and your waist at its narrowest.
TIP: Think about the garment you're shopping for when consulting the size chart. For example, When sizing for floaty dresses, your bust measurement is the most important. Size to your hips for a pair of pants, as most of our waistbands are stretchy.