heavy water: meaning, definition, pronunciation and examples
C1Technical / Scientific
Quick answer
What does “heavy water” mean?
Water in which the hydrogen atoms have been replaced by deuterium (a heavier isotope of hydrogen), making it denser than ordinary water.
Audio
Pronunciation
Definition
Meaning and Definition
Water in which the hydrogen atoms have been replaced by deuterium (a heavier isotope of hydrogen), making it denser than ordinary water.
A term used primarily in nuclear physics and chemistry for deuterium oxide (D₂O). It is used as a neutron moderator in some nuclear reactors. Can also be used metaphorically to describe something dense, sluggish, or ponderous.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Both varieties use the same term with identical meaning and application.
Connotations
Neutral scientific term in both. Potential metaphorical use would carry the same connotation of slowness or density.
Frequency
Equally low frequency in general discourse but standard in nuclear physics contexts in both regions.
Grammar
How to Use “heavy water” in a Sentence
[Heavy water] is used in [nuclear reactor].The [reactor] is moderated by [heavy water].Scientists [produce/isolate] [heavy water].Vocabulary
Collocations
Examples
Examples of “heavy water” in a Sentence
adjective
British English
- The heavy-water plant was under scrutiny.
- They discussed heavy-water moderation techniques.
American English
- The heavy-water facility required an upgrade.
- Heavy-water production is a closely monitored process.
Usage
Meaning in Context
Business
Rare, except in specific industries like nuclear energy (e.g., 'The contract includes the supply of heavy water for the new plant.').
Academic
Common in chemistry, physics, and engineering texts and lectures on nuclear technology or isotope chemistry.
Everyday
Extremely rare. May appear in news about nuclear programs or historical documentaries about WWII atomic research.
Technical
The primary domain. Used precisely to refer to D₂O as a chemical substance and reactor moderator.
Vocabulary
Synonyms of “heavy water”
Strong
Neutral
Vocabulary
Antonyms of “heavy water”
Watch out
Common Mistakes When Using “heavy water”
- Using it to describe physically viscous or muddy water. *'After the flood, the streets were full of heavy water.'
- Pronouncing it as a single stressed unit rather than a compound: /ˈheviwɔːtə/ instead of /ˌhevi ˈwɔːtə/.
FAQ
Frequently Asked Questions
In small quantities, it is not highly toxic, but drinking large amounts can be harmful because it disrupts cellular processes that depend on normal water. It is not radioactive itself.
It is an excellent moderator. It slows down fast-moving neutrons produced during fission, making them more likely to cause further fission in uranium-235, while absorbing very few neutrons itself compared to other materials.
No, they are both clear, colourless liquids. Heavy water is about 11% denser, but this is not visually apparent.
It comes from the heavier atomic weight of deuterium compared to the common hydrogen isotope (protium). A deuterium atom has a neutron in its nucleus, while common hydrogen does not.
Water in which the hydrogen atoms have been replaced by deuterium (a heavier isotope of hydrogen), making it denser than ordinary water.
Heavy water is usually technical / scientific in register.
Heavy water: in British English it is pronounced /ˌhevi ˈwɔːtə/, and in American English it is pronounced /ˌhevi ˈwɔːtər/ | /ˌhevi ˈwɑːtər/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of 'heavy' as referring to the 'heavy hydrogen' (deuterium) inside it, not that it feels thick to drink.
Conceptual Metaphor
KNOWLEDGE/SCIENCE IS WEIGHT ('heavy with scientific significance'); SLOWNESS IS WEIGHT ('The bureaucratic process moved like heavy water.').
Practice
Quiz
What is the primary defining characteristic of heavy water?