flux

/flʌks/

//flʌks// noun

By · According to Wiktionary data (CC BY-SA) ·

"flux" is a 4-letter English headword indexed on PlainSpell.

The verdict

“flux” is a moderately-common English word, ranked #13,518 in English word frequency and used as a noun.

#13,518
frequency rank, English
4
letters
6
tracked misspellings
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The act of flowing; a continuous moving on or passing by, as of a flowing stream.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

flux vs fu
50% similar
flux vs fun
50% similar
flux vs fly
50% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for flux
PropertyValue
Headwordflux
LanguageEnglish
Part of speechNoun
IPA/flʌks/
Letters4
Frequency rank#13,518
Misspellings tracked6
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “flux” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). flux lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for flux is 4 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /flʌks/. Corpus data places it at rank #13,518 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 7 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 6 likely wrong-spelling variants for flux, with forms such as "fflux", "fllux", and "fluxx". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 20 confusable-pair relationships, "fu", "fun", "fly", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From Old French flux, from Latin fluxus (“flow”). The correct English form is flux, spelled F-L-U-X.

Definition

  1. 1
    The act of flowing; a continuous moving on or passing by, as of a flowing stream.
  2. 2
    A state of ongoing change.
  3. 3
    A chemical agent for cleaning metal prior to soldering or welding.
  4. 4
    The rate of transfer of energy (or another physical quantity), especially an electric or magnetic field, through a given surface.
  5. 5
    A disease which causes diarrhea, especially dysentery.
  6. 6
    Diarrhea or other fluid discharge from the body.
  7. 7
    The state of being liquid through heat; fusion.

Etymology

From Old French flux, from Latin fluxus (“flow”).

This word in other languages

fluxión(Español)décapant(Français)Fluss(Deutsch)fluxo(Português)

Common misspellings

Also misspelled as: fflux,fllux,fluxx,flxu,fulx,lfux

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of flux - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.

fflux1fllux1fluxx1flxu2fulx2lfux2
Edit distance from "flux"

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "flux"?
"flux" is spelled F-L-U-X. The IPA pronunciation is /flʌks/.
What does "flux" mean?
As a noun, "flux" means: The act of flowing; a continuous moving on or passing by, as of a flowing stream.
What words are commonly confused with "flux"?
"flux" is commonly confused with "fu", "fun", "fly". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "flux"?
The IPA (International Phonetic Alphabet) transcription for "flux" is /flʌks/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "flux"?
From Old French flux, from Latin fluxus (“flow”). See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “flux”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is F-L-U-X - every other letter order is a misspelling in standard orthography.
  • Say it as /flʌks/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “fu” - see the side-by-side comparison. flux vs fu
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list