Midsection (noun)

1. The part of the body located between the chest and the hips.
2. The central part of something, especially a structure or object.

Origin:

From the old english 'mid' meaning 'middle' and 'sēction' meaning 'a cutting or division'.

Examples:

1. The midsection of the aircraft was severely damaged.
2. She was conscious of her expanding midsection as her pregnancy progressed.
3. The midsection of the bridge was completed ahead of schedule.
4. He was struck in the midsection and doubled over in pain.
5. The midsection of the book was particularly interesting.