Cyst (noun)

1. A sac-like structure that contains fluid or other material.
2. A closed, abnormal structure that contains fluid or a semi-solid material, often as a result of an infection, injury, or developmental abnormality.

Origin:

Derived from the greek word 'kustis' meaning 'bladder'.

Examples:

1. The cyst was surgically removed and found to contain fluid.
2. A cyst on the ovary can cause pain and discomfort, and may need to be removed.
3. A cyst can form in any part of the body and is often benign, but may need to be monitored or treated.
4. The cyst was a result of an infected wound and had to be drained.
5. The dermatologist recommended a biopsy of the cyst to determine if it was cancerous.