tach·y·lyte also tach·y·lite (tăkə-līt′)
A brown, black, or green volcanic glass formed from basaltic magma and often found along the edges of dikes, sills or volcanic flows, where rock usually forms first by contact with the cooler surrounding rock.
[German Tachylyt : Greek takhu-, tachy- + Greek lutos, soluble (from lūein, to loosen; see leu- in the Appendix of Indo-European roots).]
tach′y·lytic (-lĭtĭk) adj.
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:
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.