English
pyroclastic flow
From pyroclastic + flow.
A compound of pyroclastic + flow
Proto-Germanic *flōaną ‘to flow’
Proto-West Germanic *flōan ‘to flow’
Old English flōwan ‘to flow’
Middle English flowen
Middle English flowe
English flow
Today it means
noun A dense flow of volcanic ash, dust, rocks and debris that cascades at high speed down the slope of a volcano during an eruption.
Language periods are conventional ranges, not dates for this word.
Etymograph / pyroclastic flow