What does tuff mean?
Tuff is a geological noun for a light, porous rock formed when volcanic ash and other fragments of erupting volcanoes are compacted and cemented together. Deposits of tuff can preserve evidence of ancient eruptions, making the rock important to geologists, archaeologists, and paleontologists. The word may also be used as an informal or dialectal adjective meaning “tough,” as in “a tuff climb,” although standard English normally uses tough. Despite the sound resemblance, the geological meaning is unrelated to the familiar adjective tough. Tuff should not be confused with tufa, a related but distinct calcium-carbonate deposit. For most readers, the geological sense is the standard one, while the adjective spelling is chiefly associated with informal or regional speech.
A consolidated volcanic rock formed from compacted ash and other fragments of volcanic material.
"The road cuts through a thick layer of tuff."
Common in geology, paleontology, archaeology, and descriptions of volcanic landscapes.
An informal or dialectal variant of tough.
"They had a tuff time getting the vehicle out of the mud."
Nonstandard and chiefly informal or dialectal; use tough in formal English.
Used for distinct masses or types of tuff, although tuff is also used as a mass noun.
"The samples came from several volcanic tuffs."
Tuff sounds like tough, but in geology it is a rock made from compacted volcanic ash—proof that a memorable word can also be a geological time capsule.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Words that share this root
How tuff is actually used
The geological noun is standard in earth science and related fields. The adjective sense is nonstandard, informal, or dialectal and should normally be avoided in formal writing.
Easily confused with tuff
Tuff is the spelling for a consolidated volcanic rock and, informally, for tough; tough means difficult to break, endure, or deal with.