A woman's breast size usually indicated by her bra's cup size. Bra sizes range from AA to J. The bra size represents the relationship of the circumference of the body at the breast and the circumference of the body immediately below the breast. "AA" represents a difference of 1/2 inch or less. "DDD" represents a difference of about 6 inches, and "J" a difference of about 10".
Typically, a woman's breasts begin to develop early in puberty. They may appear to grow during pregnancy.