a. A flow or flowing of a liquid.
b. The flowing in of the tide.
c. A continuing movement, especially in large numbers of things: a flux of sensation.
2. Constant or frequent change; fluctuation: "The constant flux of people and groups ensures that human gene pools will always be mixed" (Steve Olson).
3. Medicine The discharge of large quantities of fluid material from the body, especially the discharge of watery feces from the intestines.
a. The rate of flow of fluid, particles, or energy through a given surface.
b. See flux density.
c. The lines of force of an electric or magnetic field.
5. Chemistry & Metallurgy A substance that aids, induces, or otherwise actively participates in fusing or flowing, as:
a. 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.
b. A mineral added to the metals in a furnace to promote fusing or to prevent the formation of oxides.
c. An additive that improves the flow of plastics during fabrication.
d. A readily fusible glass or enamel used as a base in ceramic work.
v. fluxed, flux·ing, flux·es
1. To melt; fuse.
2. To apply a flux to.
1. To become fluid.
2. To flow; stream.
[Middle English, from Old French, from Latin flūxus, from past participle of fluere, to flow; see bhleu- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.