What does bitumen mean?
Bitumen is a thick, black, sticky substance composed of complex hydrocarbons, found naturally in petroleum seeps and rock deposits or produced as the heavy residue left after crude oil is refined. It has been prized since antiquity—the Egyptians used it for waterproofing boats and embalming—and today its principal uses are in road construction, where it binds aggregate into asphalt pavement, and in roofing and waterproofing products such as membranes and sealants. In the petroleum industry, especially in Canada, 'bitumen' also denotes the ultra-heavy crude extracted from oil sands, which must be processed before it can be shipped or refined. The adjective 'bituminous' describes materials containing it, such as bituminous coal. Because it is a mass noun, it normally takes no plural. Though technical in register, bitumen is a useful word for anyone discussing roads, construction, geology, or energy.
nounA black, sticky, tar-like mixture of hydrocarbons obtained naturally from petroleum deposits or as a residue from refining crude oil, used chiefly in road surfacing, roofing, and waterproofing.
- A viscous black mixture of heavy hydrocarbons occurring naturally or produced by petroleum refining, used for paving, roofing, and waterproofing.
- (Geology/petroleum industry) The extra-heavy crude oil component found in oil sands such as those of Alberta, which must be upgraded or diluted before pipeline transport.
"The workers laid a fresh layer of hot bitumen over the crumbling road surface."
"Cracks in the driveway were sealed with a brushful of black bitumen."
"Canada's oil sands contain vast reserves of bitumen that require upgrading before it can be refined into gasoline."
Rarely used; bitumen is almost always an uncountable (mass) noun. A plural appears mainly in technical contexts distinguishing multiple varieties or samples of the substance.
"Laboratory tests compared the rheological properties of several bitumens recovered from different refineries."
Ancient Egyptians waterproofed mummies and boats with bitumen millennia before it paved the modern world's roads.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bitumen
Bitumen comes directly from Latin bitūmen, the Roman name for mineral pitch, a word of ultimately uncertain origin—proposals linking it to Celtic or other ancient languages remain speculative. It entered English in the early 15th century via Middle French, retaining its classical sense of natural tar-like substance. Its most prominent derivative is the adjective bituminous, formed on the same Latin stem, while the related term asphalt traces to Greek rather than Latin but names closely associated materials.
Related word forms
How bitumen is actually used
Bitumen is a technical and industrial register word, common in civil engineering, construction, and petroleum contexts rather than everyday conversation. In North American usage, 'asphalt' is the preferred general term for paving material, while 'bitumen' is retained for the pure binder and for oil-sands crude; in British and Commonwealth usage the two terms overlap considerably. The plural form is rare because the substance is uncountable in ordinary use.
Easily confused with bitumen
In American English 'asphalt' is the everyday term for the road-surfacing material, while 'bitumen' is the technical name for the binding hydrocarbon component itself; British usage treats them more interchangeably.