- a rock formed by the fusing together on the ground of small rock fragments (less than 2 mm across) ejected from a volcano
WordReference Random House Unabridged Dictionary of American English © 2026
tuff1
(tuf ),USA pronunciation adj. [Slang.]
tuff2 (tuf ),USA pronunciation n. [Geol.]
tuff•a•ceous
(tu fā′shəs),USA pronunciation adj.
- Slang Termstough (def. 13).
tuff2 (tuf ),USA pronunciation n. [Geol.]
- Geologya fragmental rock consisting of the smaller kinds of volcanic detritus, as ash or cinder, usually more or less stratified. Also called volcanic tuff.
- Italian tufo. See tufa
- French tuf
- 1560–70;
Collins Concise English Dictionary © HarperCollins Publishers::
tuff /tʌf/ n
'tuff' also found in these entries (note: many are not synonyms or translations):
tophus
- trass
- calc-tufa
- ignimbrite
- lithic
- pozzolana
- pyroclastic
- thunder egg
- tufa
- volcanic tuff
- welded tuff