petroleum

noun

pe·​tro·​leum pə-ˈtrō-lē-əm 

-ˈtrōl-yəm

: an oily flammable bituminous liquid that may vary from almost colorless to black, occurs in many places in the upper strata of the earth, is a complex mixture of hydrocarbons with small amounts of other substances, and is prepared for use as gasoline, naphtha, or other products by various refining processes

Examples of petroleum in a Sentence

Recent Examples on the Web

By the 1960s, however, geologic analyses showed these were part of an immense body of heavy petroleum, 550 km long and 45 km wide. —Scott Montgomery, Forbes.com, 25 Jan. 2026

Surveyors also noted the potential for petroleum to enter soil and groundwater from a boiler and oil tank historically used in the hotel basement, according to the grant application. —Jake Goodrick, Sacbee.com, 22 Jan. 2026

Plastic is derived from petroleum and can warp, melt, release chemicals, or catch fire when exposed to heat. —Brandee Gruener, Southern Living, 21 Jan. 2026

This infrastructure is also used by several neighboring countries including Burundi, DR Congo, Rwanda, and Uganda to transport petroleum via pipelines from the port city of Mombasa. —Martin K.n Siele, semafor.com, 19 Jan. 2026

Word History

Etymology

Middle English, "mineral oil," borrowed from Medieval Latin, "mineral oil, crude oil," from Latin petra "rock" (borrowed from Greek pétra) + oleum "oil" — more at petro-, oil entry 1

First Known Use

15th century, in the meaning defined above

Phrases Containing petroleum

• liquefied petroleum gas
• petroleum jelly

Rhymes for petroleum

• folium
• lolium
• oleum
• scholium
• linoleum
• trifolium
• tetrazolium

Kids Definition

petroleum

noun

pe·​tro·​leum pə-ˈtrō-lē-əm 

-ˈtrōl-yəm

: an oily flammable liquid that may vary from almost colorless to black, is obtained from wells drilled in the ground, and is the source of gasoline, kerosene, fuel oils, and other products

Medical Definition

petroleum

noun

pe·​tro·​leum pə-ˈtrō-lē-əm, -ˈtrōl-yəm 

: an oily flammable bituminous liquid that may vary from almost colorless to black, occurs in many places in the upper strata of the earth, is a complex mixture of hydrocarbons with small amounts of other substances, and is prepared for use as gasoline, naphtha, or other products by various refining processes