lava

the word "lava" entered english in the mid-18th century from the italian word "lava," meaning "a stream caused by sudden rain." this italian term itself likely derives from the latin verb "lavare," meaning "to wash." the semantic shift is logical: the flowing, destructive nature of a torrent of water was metaphorically applied to the streams of molten rock flowing from volcanoes, particularly those in italy like vesuvius. the connection to "washing" may also allude to the way lava can scour and cleanse a landscape. thus, a term for a sudden flood evolved, via italian vulcanology, into the specific geological term we use today.

this word is a simplex loanword from italian. it does not contain separable morphemes within its modern english spelling.