observable
- 01 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.
Simple“The changes in the weather were observable even without special equipment.”
In context“The researchers noted that the chemical reaction produced an observable change in color within seconds of the two liquids being mixed.”
SynonymsAntonymsinvisibleunobservable - 02 C1 Advanced
n.a physical property that a scientist can measure directly.
n.a physical quantity or property that can be measured directly in an experiment.
Simple“Temperature is an observable that helps us understand how a system changes.”
In context“In quantum mechanics, an observable is represented by an operator that acts on the state of the physical system.”
UsageIn physics, this is often used as a countable noun.
“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.”
From observe + -able.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.