The waist's the part of the abdomen between the rib cage and hips. On proportionate people, the waist's the narrowest part of the torso. Waistline refers to the horizontal line where the waist's narrowest, or to the general appearance of the waist. People who diet are often said to be trying to "improve" their waistline. Women tend to have narrower waists than men in most cases. Fashion The waistline of clothing generally corresponds to the human waist. Traditionally belts are worn around the w… (More on Waist)