pe·​trol·​o·​gy pə-ˈträ-lə-jē How to pronounce petrology (audio)
: a science that deals with the origin, history, occurrence, structure, chemical composition, and classification of rocks
petrologic adjective
or petrological
petrologically adverb
petrologist noun

Example Sentences

Recent Examples on the Web Her work and dedication helped establish the igneous petrology (the study of magma) and geothermal branch of the USGS. Erik Klemetti, Discover Magazine, 27 Mar. 2023 Belfanti was pursuing a doctorate in igneous petrology at Vanderbilt University in Nashville, before moving to Melrose, where his parents were living, in 2018. Jon Chesto,, 20 Mar. 2023 Even their ultimate source isn't well understood -- one of the great mysteries in petrology. Erik Klemetti, Discover Magazine, 11 Mar. 2014 Finally, in early August I’ll be headed to a SERC workshop on teaching mineralogy, petrology and geochemistry in Minneapolis – Erik Klemetti, WIRED, 7 June 2011

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'petrology.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


petro- + -logy

First Known Use

1811, in the meaning defined above

Time Traveler
The first known use of petrology was in 1811

Dictionary Entries Near petrology

Cite this Entry

“Petrology.” Dictionary, Merriam-Webster, Accessed 3 Jun. 2023.

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