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dif·fu·sion (dĭ-fyzhən)
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n.
1. The process of diffusing or the condition of being diffused: the diffusion of new technology around the world.
2. Physics
a. The scattering of incident light by reflection from a rough surface.
b. The transmission of light through a translucent material.
c. The spontaneous intermingling of the particles of two or more substances as a result of random thermal motion.
3. The spread of linguistic or cultural practices or innovations within a community or from one community to another.
dif·fusion·al adj.
(click for a larger image)
diffusion
In the process of diffusion of a single solute, a concentration of molecules on one side of a membrane (top) will move through a membrane (center) until there is equilibrium on both sides (bottom).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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:

    Indo-European Roots

    Semitic Roots

    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.

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