tuff2+ (tuf)

An old spelling of tough. tuff3 (tuf), n. [F. tuf, formerly also tuffe, soft stone, It. tufo, soft stone, tufa, tufa, IMG:content-1037.png:[graphic] does not differ, except in color and degree of compactne , from the modern sperone ( lapis Gabinus ), or from the so called manziana ( lapis An it i an us ). These are all fragmental rocks made up of more or le firmly compacted volcanic cinders and ashes, and are all included under the term tuff as used by English geologists.