# caustic

/ˈkɑstɪk/ (US) · /kˈɔːstɪk/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/caustic
Updated: 2026-05-18

## Definition

a substance that can burn or damage things it touches. It is often used to describe strong chemicals like bleach or acid.

For teachers: a substance that is capable of burning or corroding living tissue or other organic matter. Often used to describe strong alkalis or acids that cause chemical burns upon contact.

## Examples

- The worker wore thick gloves to handle the caustic cleaner.
- The lab safety manual warns that the caustic solution must be diluted before it is poured down the drain.
- While the chemical is essential for industrial cleaning, its caustic nature requires strict safety protocols to prevent accidental exposure to the skin or eyes.

---

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.