Word
observable
Phoneticsob·serv·able
US/əbˈzɝvəbəɫ/
UK/ɒbzˈɜːvəbəl/
Definitions
01able to be seen
B2 · Upper Intermediate
adj. able to be seen, noticed, or measured.
adj. capable of being perceived or noticed; discernible through the senses or scientific instruments.
“The changes in the weather were observable even without special equipment.”
“The researchers noted that the chemical reaction produced an observable change in color within seconds of the two liquids being mixed.”
Synonyms
Antonyms
02measurable property
C1 · Advanced Countable noun Science Technical
n. a physical property that a scientist can measure directly.
n. a physical quantity or property that can be measured directly in an experiment.
“Temperature is an observable that helps us understand how a system changes.”
“In quantum mechanics, an observable is represented by an operator that acts on the state of the physical system.”
Usage
In physics, this is often used as a countable noun.
Real-World Examples
“Traces left behind by organisms may not survive over time, observable signals may be too faint to identify, or existing technologies may simply be unable to detect them.” “Astronomers estimate that the observable universe contains roughly 1 trillion galaxies.” Etymology
From observe + -able.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
VERB
ADJECTIVE
Domain
- 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
- Occasional
- Level
- B2 · Upper Intermediate
- Updated
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QR code
englishreference.com/q/observable