flux

UK: /ˈflʌks/ US: /flʌks/ ,(fluks)

WordReference Random House Learner's Dictionary of American English © 2025

flux /flʌks/   n. 

1. a flowing or flow:
   [countable] a flux of traffic.
2. continuous change or movement:
   [uncountable] Our plans are in a state of flux.

See -flu-.

WordReference Random House Unabridged Dictionary of American English © 2025

flux  (fluks), n. 

1. a flowing or flow.
2. the flowing in of the tide.
3. continuous change, passage, or movement:
   His political views are in a state of flux.
4. Physics
   • the rate of flow of fluid, particles, or energy.
   • a quantity expressing the strength of a field of force in a given area.
5. Chemistry, Metallurgy
   • a substance used to refine metals by combining with impurities to form a molten mixture that can be readily removed.
   • a substance used to remove oxides from and prevent further oxidation of fused metal, as in soldering or hot-dip coating.
   • (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.

v.t. 

7. to melt;
   make fluid.
8. to fuse by the use of flux.
9. [Obs.] to purge.

v.i. 

10. to flow.

• Latin fluxus a flowing, equivalent. to fluc-, variant stem of fluere to flow + -tus suffix of verb, verbal action, with ct x
• Middle English 1350–1400

Synonyms

• 1. course, current, flood, stream.

Collins Concise English Dictionary © HarperCollins Publishers::

flux / 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. a chemical used to increase the fluidity of refining slags in order to promote the rate of chemical reaction
5. 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)
6. 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. an excessive discharge of fluid from the body, such as watery faeces in diarrhoea

verb

1. to make or become fluid
2. (transitive) to apply flux to (a metal, soldered joint, etc)
3. (transitive)
   an obsolete word for purge

Etymology: 14th Century: from Latin fluxus a flow, from fluere to flow