# deuterium

/duˈtiɹiəm/ (US) · /djuːtˈiəɹɪəm/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/deuterium
Updated: 2026-10-14

## Definition

a heavy form of hydrogen that has an extra particle in its center, so it weighs about twice as much. It exists in tiny amounts in nature, mostly in water.

For teachers: a stable isotope of hydrogen with one proton and one neutron in the nucleus, about twice the mass of common hydrogen. Occurs naturally in very small amounts, most familiarly in heavy water.

## Examples

- Heavy water contains a form called deuterium.
- Scientists track deuterium in ice cores to learn about past climates.
- Because deuterium fuses more readily than ordinary hydrogen, researchers view it as a promising fuel for future fusion reactors.

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