invariant

IPA/ɪnˈveəriənt/
KK[ˌɪnvˈɛriənt]IPA/ɪnˈveriənt/

invariant — adjective

  • invariantpositive
  • more invariantcomparative
  • most invariantsuperlative

1. remaining the same under all conditions; never changing in form, value, or quali

1.adjectiveC1
Definition

remaining the same under all conditions; never changing in form, value, or quality

Example

The physical laws that Daichi studied in class are invariant across space and time.

invariant across [space/time]

One invariant rule of the lab is that all equipment must be returned before closing.

collocation: invariant rule

Common collocations
  • invariant across
  • invariant under
  • remain invariant
  • invariant property
  • invariant rule
  • invariant feature
Synonyms
  • constant

    more common and less formal; used freely in everyday and technical contexts

  • unchanging

    simpler and more direct; common in both casual and formal writing

  • unvarying

    similar formality to invariant but slightly less common; emphasizes lack of variation

Antonyms
  • variable

    the direct opposite; something that changes or can be changed

  • changing

    simple everyday opposite

Usage Note

Typically used in formal, academic, or scientific contexts. Describes a property that stays the same across different conditions or over time, rather than a temporary lack of change.

Common Mistakes

The weather has been invariant all week.
The weather has been steady all week.
'invariant' describes a fixed property across varying situations, not a period of no change.
She kept an invariant smile on her face.
She kept a fixed smile on her face.
'invariant' suggests a mathematical or scientific constancy, not a temporary physical state.

Word family

Synonym discussion

Sense: adjective/1

'Constant' and 'unchanging' are the most common alternatives to 'invariant'. 'Constant' is used across everyday and technical language (a constant temperature, a constant friend) and is much more frequent. 'Unchanging' is simpler and more direct, often describing visible or experiential stability (unchanging landscape, unchanging routine). 'Unvarying' is close in formality to 'invariant' but emphasises the absence of any variation across repeated instances. 'Uniform' differs in meaning — it describes things that are the same across a group or area (uniform sizes, uniform standards), not necessarily over time. Use 'invariant' when you want a precise, formal term for something that remains identical regardless of changing conditions, especially in scientific or mathematical contexts: 'The speed of light in a vacuum is an invariant constant in physics.' For everyday situations, 'constant' or 'steady' usually sound more natural.

constant ↗unchanging ↗unvarying ↗uniform ↗

Common collocations

Nouns

Adverbs

Phrases

  • time-invariant
  • scale-invariant
  • remain invariant
  • proved invariant

Prepositions

Etymology

LatinEnglish

From Latin 'invariantem', combining 'in-' (not) and 'variantem' (changing), a form of the verb 'variare' (to vary). The word entered English in the mid-19th century, first used in mathematics and science to describe quantities or properties that remain unchanged under specified operations.