English Reference

Word

vapor

Phoneticsva·por, stress on the first syllable

US/ˈveɪpɝ/

UK/vˈeɪpɐ/

UK spelling · vapour

Definitions

01mist or steam

B2 · Upper Intermediate Uncountable noun American English

n. a cloud of very small drops of liquid in the air, like steam or mist.

n. a visible suspension of fine particles or droplets in the air, such as mist, steam, or fumes.

“The morning sun caused a thick vapor to rise from the lake.”

“As the temperature dropped, a dense vapor began to cling to the valley floor, reducing visibility for the early morning commuters.”

Usage

Uncountable when referring to the general substance; countable when referring to specific types or clouds.

Synonyms

02gaseous state

C1 · Advanced Uncountable noun Science American English · Technical

n. the gas form of something that is usually a liquid or solid.

n. the gaseous phase of a substance that normally exists as a liquid or solid at standard temperature and pressure.

“Water turns into vapor when it reaches its boiling point.”

“The laboratory was equipped with specialized ventilation to extract the toxic chemical vapors produced during the experiment.”

Usage

Commonly used in chemistry and physics contexts.

Synonyms

gas

Antonyms

03the vapors

C2 · Proficiency Plural noun American English · Archaic

n. an old-fashioned way to describe feeling nervous, dizzy, or sad.

n. a historical term for a state of depression, hysteria, or nervous faintness.

“In the old novel, the lady suffered from the vapors after hearing the bad news.”

“The Victorian protagonist was prone to the vapors, frequently requiring a quiet room and smelling salts to recover her composure.”

Usage

Almost always used in the plural form as 'the vapors'.

Teaching tip

This is mostly found in 18th and 19th-century literature; modern speakers only use it humorously.

04to turn into gas

C1 · Advanced Science American English · Technical

v. to turn into a gas or to give off steam.

v. to convert into vapor or to emit substances in a gaseous state.

“The liquid began to vapor as it was heated on the stove.”

“The volatile compounds will vapor quickly if left uncovered in a warm environment.”

Usage

Intransitive in this sense.

Synonyms

Antonyms

Real-World Examples

“Warm air can hold more water vapour than cold air.”
The Guardian 30 Sept 2026
“Think of water vapor, liquid water and ice.”
Phys.org 20 Sept 2026

Etymology

From Middle English vapour, from Anglo-Norman vapour, Old French vapor, from Latin vapor (“steam, heat”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

NOUN

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944
Frequency
Frequent
Level
B2 · Upper Intermediate
Updated

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