noun

1. the part of the body between the ribs and the hips
2. 1. the part of a garment that covers the waist
   2. waistline (sense )
   3. the part of a garment covering the body from the shoulders to a line above the hips
   4. the upper part of a woman's dress; bodice
   5. Archaic blouse
3. the narrow part of any object that is wider at the ends the waist of a violin
4. Aeron. the middle section of the fuselage of an airplane, esp. a bomber
5. Naut. the central section of a ship; specif., the part of the deck between the forecastle and the quarterdeck
6. Zool. the narrow part of the front of the abdomen of certain insects, as ants or wasps

Etymology: ME wast < base of OE weaxan, to grow, wax: sense development: growth (of body), hence size, thickness