flux

American  

[fluhks] / flʌks /

noun

1. a flowing or flow.

   Synonyms:

   livestream, flood, current, course

2. the flowing in of the tide.

3. continuous change, passage, or movement.

   His political views are in a state of flux.

4. Physics.

   1. the rate of flow of fluid, particles, or energy.

   2. a quantity expressing the strength of a field of force in a given area.

5. Chemistry, Metallurgy.

   1. a substance used to refine metals by combining with impurities to form a molten mixture that can be readily removed.

   2. a substance used to remove oxides from and prevent further oxidation of fused metal, as in soldering or hot-dip coating.

   3. (in the refining of scrap or other metal) a salt or mixture of salts that combines with nonmetallic impurities, causing them to float or coagulate.

6. fusion.

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verb (used with object)

1. to melt; make fluid.

2. to fuse by the use of flux.

3. Obsolete. to purge.

verb (used without object)

1. to flow.

flux British  

/ flʌks /

noun

1. a flow or discharge

2. continuous change; instability

3. a substance, such as borax or salt, that gives a low melting-point mixture with a metal oxide. It is used for cleaning metal surfaces during soldering, etc, and for protecting the surfaces of liquid metals

4. metallurgy a chemical used to increase the fluidity of refining slags in order to promote the rate of chemical reaction

5. a similar substance used in the making of glass

6. physics

   1. the rate of flow of particles, energy, or a fluid, through a specified area, such as that of neutrons ( neutron flux ) or of light energy ( luminous flux )

   2. the strength of a field in a given area expressed as the product of the area and the component of the field strength at right angles to the area

      magnetic flux

      electric flux

7. pathol an excessive discharge of fluid from the body, such as watery faeces in diarrhoea

8. the act or process of melting; fusion

9. (in the philosophy of Heraclitus) the state of constant change in which all things exist

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verb

1. to make or become fluid

2. (tr) to apply flux to (a metal, soldered joint, etc)

3. (tr) an obsolete word for purge

flux Scientific  

/ flŭks /

1. The rate of flow of fluids, particles, or energy across a given surface or area.

2. The presence of a field of force in a region of space, represented as a set of lines indicating the direction of the force. The density of the lines indicates the strength of the force. Lines used to represent magnetic fields in depictions of magnets, for example, follow the lines of flux of the field.

3. See also field magnetic flux

4. A measure of the strength of such a field.

5. A readily fusible glass or enamel used as a base in ceramic work.

6. An additive that improves the flow of plastics during fabrication.

7. A substance applied to a surface to be joined by welding, soldering, or brazing to facilitate the flowing of solder and prevent formation of oxides.

8. A substance used in a smelting furnace to make metals melt more easily.

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Other Word Forms

• nonflux
  noun
• superflux
  noun
• transflux
  noun

Etymology

Origin of flux

First recorded in 1350–1400; Middle English, from Latin fluxus “a flowing,” equivalent to fluc-, variant stem of fluere “to flow” + -tus, noun and participle suffix

Explanation

The noun flux describes something that constantly changes. If your likes, dislikes, attitudes, dreams, and even friends are changing all the time, you may be in flux. Flux can also mean being unsure about a decision. Suppose you just had a great job interview and suddenly your friend invites you to go to Australia with her. You don't know what to do because you don't want to miss a call about the job — or Sydney! You're in flux until you hear from the potential employer. Another kind of flux is liquid moving or flowing, like the flux of water under a sheet of melting ice.

Example Sentences

In an axial flux motor, the electromagnetic field is parallel to the motor’s axis of rotation, instead of perpendicular in a conventional electric motor.

From Barron's • May 20, 2026

The complex tax system the governor proposed would be carried out in two phases, though many questions remain and details of the plan are still in flux.

From The Wall Street Journal • May 15, 2026

Oscars viewership has been in flux as younger audiences prefer to view clips of the ceremony on social media, rather than on television.

From Los Angeles Times • May 12, 2026

For all the talk of batting changes, it is England's pace-bowling department that is in the biggest state of flux.

From BBC • May 11, 2026

A flux of circumstances delivered the Laughing Man’s best friend, his timber wolf, Black Wing, into a physical and intellectual trap set by the Dufarges.

From "Nine Stories" by J. D. Salinger