# carbonate

/ˈkɑɹbəˌneɪt/ (US) · CEFR C1 · Noun

Source: https://englishreference.com/word/carbonate
Updated: 2026-05-07

## Definition

a chemical compound that contains carbon and oxygen. You often find these in rocks like limestone or in fizzy drinks.

For teachers: a salt or ester of carbonic acid, containing the anion CO3 2−. Often refers to minerals found in the earth's crust or chemical additives in industrial processes.

## Examples

- Calcium carbonate is the main ingredient in chalk.
- The geologist identified the rock as a type of carbonate because it reacted with the acid solution.
- The accumulation of marine organism shells on the ocean floor eventually forms thick layers of sedimentary carbonate rock over millions of years.

## Usage notes

- Uncountable when referring to the chemical substance in general; countable when referring to specific chemical varieties or salts.

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