intr.v. e·rupt·ed, e·rupt·ing, e·rupts
a. To throw or force something out violently, as lava, ash, and gases: The volcano erupted.
b. To be thrown or forced out: Water erupted from the geyser.
2. To develop suddenly: Violence erupted during the protests.
3. To express oneself suddenly and loudly: He erupted in anger.
a. To break through the gums in developing. Used of teeth.
b. To appear on the skin. Used of a rash or blemish.
[Latin ērumpere, ērupt- : ē-, ex-, ex- + rumpere, to break; see reup- in the Appendix of Indo-European roots.]
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.