# chlorine

/ˈkɫɔɹin/ (US) · /klˈɔːɹiːn/ (UK)

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

## Senses

### 1. chemical element

noun · CEFR B2 · Technical

a yellow-green gas that is a chemical element. It is very toxic but useful for making many products.

For teachers: a toxic, gaseous chemical element (symbol Cl) with an atomic number of 17. Uncountable in its general sense.

- The scientist explained how chlorine reacts with other elements to form salt.
- Chlorine is a highly reactive halogen that is never found in its elemental state in nature, occurring instead in various ionic compounds.

### 2. cleaning agent

noun · CEFR B2

a chemical used to kill bacteria in swimming pools or to clean water.

For teachers: a chlorine-based disinfectant or bleach used for water purification and sanitation.

- The smell of chlorine at the public pool was very strong today.
- The maintenance crew added extra chlorine to the pool to ensure the water remained sanitary during the heatwave.

## Examples

- The pool water smells strong because of the chlorine.
- The city adds chlorine to the drinking water to keep it safe.
- Chlorine is a powerful oxidizing agent that effectively destroys bacteria and viruses in municipal water supplies.

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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.