Waistline (noun)

1. The natural or artificial line encircling the waist marking the division between the abdomen and the hips.
2. The measurement of the circumference of the waist.

Origin:

From the word "waist" and the noun suffix "-line".

Examples:

1. She was trying to lower her waistline.
2. His waistline was expanding.
3. The dress had a high waistline.
4. The waistline measurement is used to determine obesity.
5. The waistline of the pants was too tight.