Petroleum

How to spell petroleum

9 letters · 4 syllables

How to pronounce petroleum

Say the part in capitals loudest.

What does petroleum mean?

1. nounA naturally occurring flammable oil extracted from underground, refined into fuels, lubricants, and chemical products.

Petroleum in a sentence

• The country's economy depends heavily on exporting petroleum.

• Refineries process crude petroleum into petrol, diesel, and plastics.

Where does petroleum come from?

Language of origin: Latin

This word is a hybrid built from two ancient languages: the Greek petra, meaning 'rock' or 'stone', and the Latin oleum, meaning 'oil', so it literally describes 'rock oil', the oily substance that seeps from or is drawn out of rocky ground. The compound petroleum took shape in Medieval Latin, where scholars combined the two roots to name the natural mineral oil that ancient peoples had long collected from surface seepages. English adopted it in the 1500s, well before the industrial drilling era, to describe this naturally occurring crude oil. The petra element is the same root that gives us 'petrify' (to turn to stone) and the name Peter, while oleum survives in 'oleaginous' and in the everyday word 'oil' itself. Keeping that 'rock plus oil' image in mind helps with the tricky middle: the -ole- comes straight from oleum, and the word closes with the Latin -eum, not a simpler -ium.

How the word is built

• petr- (rock, from Greek petra)
• oleum (oil, from Latin)
• -um (Latin neuter noun ending)