petro-

¹

1. a combining form meaning “rock,” “stone,” used in the formation of compound words.

   petrology.

petro-

²

1. a combining form meaning “petroleum,” “the extraction and export of petroleum,” used in the formation of compound words.

   petrochemistry; petropower.

petro

³

[pe-troh]

adjective

1. of or relating to petroleum or the petroleum industry.

noun

1. Canadian.,  the federally owned petroleum industry.

petro-

combining form

1. indicating stone or rock

   petrology

2. indicating petroleum, its products, etc

   petrochemical

3. of or relating to a petroleum-producing country

   petrostate

Word History and Origins

Origin of petro-¹

< Greek, combining form of pétra rock, pétros a stone

Origin of petro-²

Extracted from petroleum

Origin of petro-³

First recorded in 1970–75; independent use of petro- ²

Word History and Origins

Origin of petro-¹

from Greek petra rock or petros stone

Example Sentences

Maduro has previously accused Washington of "fabricating a new war", while Colombian President Gustavo Petro has said the strikes on boats are being used by the US to "dominate" Latin America.

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Colombian President Gustavo Petro has previously described the attacks as "murder" and said they were being used by the US to "dominate" Latin America.

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Following Petro's comments, the US placed sanctions on him and his inner circle, as well as removing Colombia's certification as an ally in the war on drugs.

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Petro called the operation part of a scheme to topple the leftist government in neighboring Venezuela.

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While Venezuela’s Maduro and Colombia’s Petro sit atop the bad-hombre list, Argentine President Javier Milei and El Salvador’s Nayib Bukele — the latter the self-described “world’s coolest dictator” — are the darlings of the moment.

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When To Use

What does petro- mean?

Petro- is a combining form used like a prefix that has two distinct senses.The first of these senses is “rock” or "stone," and this form of petro- is occasionally used in a variety of scientific and technical terms. Petro- comes from Greek pétra, meaning “rock.” Two Latin translations of pétra are lapis and saxum, both meaning “stone,” which are the roots of terms such as lapis lazuli and saxifrage, respectively. To learn more, check out our entries for both words.The second of these senses is “petroleum,” and this form of petro- is occasionally used in a variety of technical terms. Petro- is an abbreviation of the word petroleum, from the Medieval Latin word for "rock oil; the -oleum element means "oil" in Latin. Find out more about the word petroleum at our entry for the word.What are variants of petro- with the sense “rock”?Petri- is a variant of petro-, which exchanges its -o- for an -i- when combined with words or word elements beginning with certain consonants. Another variant for petro- in this sense is petr-, which loses its -o- combined with words or word elements beginning with vowels. Want to know more? Read our Words That Use articles for petri- and petr-.Not every word that begins with the exact letters petro- or petr-, such as petronel or petrel, is necessarily using the combining form petro- to denote “rock” or "petroleum.” Learn why petrel is the name of a seabird at our entry for the word.