Definition of "Waistline"

While you may not know your waistline measurement or where to find your natural waistline, you probably do know you want yours to be trim and shapely. The waistline has gone from a helpful construct in apparel manufacturing to an industry that includes diet pills and specialized exercise gear. But before you can sculpt it and show it off, you need to measure it and learn how it functions in terms of your personal health and style.

Definition

According to Webster's New World College Dictionary, your "waistline" is an imaginary line that circles your waist, falling between your ribs and hips. In terms of anatomy, your waistline encompasses your abdominal muscles and your obliques. Seamstresses and tailors will measure your waistline in inches; many items of clothing including men's slacks and women's denim are sold by waistline size.

Finding Your Waistline

You can find your natural waistline in one of two ways. If you have a narrow waist with a clearly defined inward curve, slip a tape measure around the narrowest part and jot down the measurement in inches. If you don't have a defined curve, you can use a piece of string to find your natural waistline. According to Kate Perri in "Pattern-Free Fashions & Accessories," tie a piece of string around your waist and bend from side to side. As you bend, the string will settle around your natural waistline. Measure the circumference of the place your string settles to find your waistline in inches.

Body Types and Waistline

Clothing designers and style advisers use terms such as "short-waisted" or "long-waisted" to describe particular body types. According to "InStyle" magazine's "Secrets of Style" book, if the measurement between your bottom rib and the top of your hip is three or fewer inches, you're short-waisted. If the measurement is four or more inches, you're long-waisted. Short-waisted body types, they note, should wear lower waistlines and long-waisted body types look best in higher waistlines.

Health and Waistline

According to the American Heart Association, the size of your waistline may indicate your overall state of health. They suggest comparing your waistline measurement to your body mass index measurement, available from their online calculator listed as a resource below. If your BMI is 25 or more, they suggest you keep your waistline under 35 inches for women and under 40 inches for men. People with large waistlines and too much fat stored in the belly area are at a higher risk for diseases such as diabetes, high cholesterol and high blood pressure.

Shaping Your Waistline

If you'd like to trim your waistline, you have to work your ab muscles. The American Council on Exercise suggests bent-knee crunches that target your rectus abdominus muscles, transverse abdominus muscles and obliques --- areas encompassing the "spare tire" or "love handles." To do this exercise, lie on your back with your hands behind your head, feet flat on the floor and knees bent. Exhale, contract your stomach muscles and bring your chest toward your legs until the top half of your back is off the ground. To finish, inhale and slowly lower yourself back to your starting position.