n. A sphere shaped droplet of molten lava ejected from a volcanic eruption which falls to earth while still at least partially molten, ranging in size from 2 to 6 millimeters.
the GNU version of the Collaborative International Dictionary of English
noun-plural. Volcanic ashes, consisting of small, angular, stony fragments or particles.
Word Usage
"Gold mineralization found at the Burns Block to date occurs near the upper contact of a distinctive fragmental volcanic rock identified as a lapilli tuff."