# colloidal

/kəˈɫɔɪdəɫ/ (US) · /kˈɒlɔɪdəl/ (UK) · CEFR C1 · Adjective

Source: https://englishreference.com/word/colloidal
Updated: 2026-10-19

## Definition

describing a liquid with very tiny bits of something spread evenly through it, so it looks smooth and does not separate quickly.

For teachers: Relating to a mixture in which microscopic particles are evenly dispersed throughout another substance without dissolving. Often describes stable suspensions such as milk, fog, or gel.

## Examples

- Milk looks white because of its colloidal mix of fat and water.
- The pharmacist shakes the bottle because the colloidal medicine separates if it sits too long.
- Researchers studied the colloidal gold particles in the solution to improve drug delivery to damaged cells.

---

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.