# cyst

/ˈsɪst/ (US) · /sˈɪst/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/cyst
Updated: 2026-05-08

## Definition

a small, closed bag or lump under the skin or inside the body that is filled with fluid or air. Most are not dangerous, but a doctor might need to check them.

For teachers: an abnormal, sac-like pocket of membranous tissue containing fluid, air, sebum, or other materials. Can occur anywhere in the body and is typically distinct from an abscess as it is not necessarily infected.

## Examples

- The doctor removed a small cyst from my wrist.
- While most skin cysts are benign and painless, they can become inflamed or infected if they are squeezed or irritated.
- The ultrasound revealed a fluid-filled ovarian cyst, which the specialist monitored over several months to ensure it would resolve naturally without surgical intervention.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.