A minute life form; a microorganism, especially a bacterium that causes disease. Not in technical use.
[French : Greek mīkro-, micro- + Greek bios, life; see gwei- in the Appendix of Indo-European roots.]
mi·crobi·al (mī-krōbē-əl), mi·crobic (-krōbĭk) adj.
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.