coeloms

/K OW0 EH1 L AH0 M Z/
noun
  1. 1

    A fluid-filled cavity within the body of an animal. The digestive system is suspended within the cavity, which is lined by a tissue called the peritoneum.

Source: https://en.wiktionary.org/wiki/coelom, https://en.wiktionary.org/wiki/coeloms