1. One that diffuses, as:
a. A light fixture, such as a frosted globe, that spreads light evenly.
b. A medium that scatters light, used in photography to soften shadows.
c. A device, such as a cone or baffle, placed in front of a loudspeaker diaphragm to diffuse the sound waves.
2. A flow passage in a wind tunnel that decelerates a stream of gas or liquid from a high to a low velocity.
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:
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.