tho·​lei·​ite ˈtō-lə-ˌīt How to pronounce tholeiite (audio) ˈthō- How to pronounce tholeiite (audio)
: a basaltic rock that is rich in aluminum and low in potassium, is found typically in the ocean floor, and is probably derived from the earth's mantle
tholeiitic adjective

Word History


German Tholeiit, from Tholey, village in Saarland, Germany + German -it -ite

First Known Use

1866, in the meaning defined above

Time Traveler
The first known use of tholeiite was in 1866

Dictionary Entries Near tholeiite

Cite this Entry

“Tholeiite.” Dictionary, Merriam-Webster, Accessed 20 Apr. 2024.

More from Merriam-Webster on tholeiite

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!