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di·a·base (dīə-bās)
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n.
A dark-gray to black, fine-textured igneous rock composed mainly of feldspar and pyroxene and used for monuments and as crushed stone.

[From French diabase, originally meaning “diorite,” (now “basalt or gabbro lightly modified by metamorphism”), coined by French mineralogist Alexandre Brongniart (1770-1847), probably from Greek diabasis, a crossing over (from diabainein, to pass through or over; see DIABETES; the rock being so called because it is often found as intrusive sills and dikes in other rocks), or perhaps an alteration of an intended French *dibase (di-, two, from Greek di-; see DI-1 + base, basis, from Old French; see BASE1; the rock being so called in reference to feldspar and amphibole, two important constituent minerals of diorite).]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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:

    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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