la·va (lävə, lăvə)
1. Molten rock that reaches the earth's surface through a volcano or fissure.
2. The rock formed by the cooling and solidifying of molten rock.
[Italian, perhaps from Latin lābēs, fall, from Latin lābī, to fall.]
Word History: Appropriately, lava was named by people living near Mount Vesuvius. The only active volcano on the European mainland, Vesuvius has erupted frequently since Pompeii and Herculaneum were buried by it in AD 79. The Neapolitans who lived in the vicinity took the Italian word lava, meaning "a stream caused suddenly by rain," and applied it to the streams of molten rock coming down the sides of Vesuvius. The term was then taken into Standard Italian, where it came to mean the rock in both its molten and its solidified states. The Italian word was borrowed into English around the middle of the 18th century.
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.