black body: meaning, definition, pronunciation and examples

C2
UK/ˌblæk ˈbɒdi/US/ˌblæk ˈbɑːdi/

Technical/Scientific

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Quick answer

What does “black body” mean?

An idealised physical object that absorbs all electromagnetic radiation falling on it, regardless of frequency or angle of incidence.

Audio

Pronunciation

Definition

Meaning and Definition

An idealised physical object that absorbs all electromagnetic radiation falling on it, regardless of frequency or angle of incidence.

A theoretical concept in physics used to model perfect absorption and emission of radiation, serving as a standard against which real objects are compared. It is also sometimes used in materials science to refer to objects or coatings designed to approximate this ideal.

Dialectal Variation

British vs American Usage

Differences

No significant lexical or spelling differences. The concept is identical in both scientific communities.

Connotations

Purely technical with no regional connotative differences.

Frequency

Equally low-frequency and confined to specialised scientific discourse in both regions.

Grammar

How to Use “black body” in a Sentence

The [material] acts as a black body.Scientists calculated the [property] using a black-body model.[Object] approximates an ideal black body.

Vocabulary

Collocations

strong
black-body radiationideal black bodyperfect black bodyblack-body spectrum
medium
approximates a black bodybehaves as a black bodyblack-body temperatureblack-body curve
weak
study the black bodyconcept of a black bodymodel of a black body

Examples

Examples of “black body” in a Sentence

adjective

British English

  • The black-body radiation spectrum was precisely measured.

American English

  • The black-body radiation spectrum was precisely measured.

Usage

Meaning in Context

Business

Extremely rare, except perhaps in highly technical industries like aerospace or advanced materials.

Academic

Core term in physics, astronomy, and engineering thermodynamics courses and research.

Everyday

Virtually never used.

Technical

Essential term in physics, astrophysics (e.g., cosmic microwave background), optical engineering, and thermal imaging.

Vocabulary

Synonyms of “black body”

Strong

Planckian radiator

Neutral

perfect absorberideal radiator

Weak

full absorber

Vocabulary

Antonyms of “black body”

white body (theoretical perfect reflector)grey body (imperfect absorber/emitter)

Watch out

Common Mistakes When Using “black body”

  • Using 'black body' to describe a physically dark object (e.g., 'The car was a black body in the night').
  • Omitting the hyphen when used as a compound modifier (e.g., 'black-body radiation' is correct, 'black body radiation' is less standard).
  • Confusing it with 'black hole', which is a different astrophysical concept.

FAQ

Frequently Asked Questions

Not necessarily. While it absorbs all radiation, it also emits radiation according to its temperature. A hot black body glows (e.g., the sun approximates a black body and is bright). The term refers to its perfect absorption, not its visual appearance.

It is the thermal electromagnetic radiation emitted by a black body. The spectrum and intensity of this radiation depend solely on the body's temperature, as described by Planck's law.

No, it is an idealised theoretical model. However, certain objects like cavities with a small hole, or some specialised nanomaterials, can approximate its properties very closely.

It was crucial in the development of quantum mechanics (solving the ultraviolet catastrophe) and remains fundamental in astrophysics, thermodynamics, and remote sensing for calculating temperatures and radiation from stars, planets, and materials.

An idealised physical object that absorbs all electromagnetic radiation falling on it, regardless of frequency or angle of incidence.

Black body is usually technical/scientific in register.

Black body: in British English it is pronounced /ˌblæk ˈbɒdi/, and in American English it is pronounced /ˌblæk ˈbɑːdi/. Tap the audio buttons above to hear it.

Learning

Memory Aids

Mnemonic

Think of a 'body' that is so 'black' it swallows all light and heat completely, never reflecting any – that's the theoretical ideal.

Conceptual Metaphor

THE UNIVERSE AS A BLACK BODY (used in cosmology to model the radiation of the early universe).

Practice

Quiz

Fill in the gap
The cosmic microwave background radiation has a spectrum that almost perfectly matches that of a .
Multiple Choice

What is the primary characteristic of an ideal black body?