'tephra' originates from Greek, specifically the word 'tephra' (τέφρα), where 'tephra' meant 'ash'.

'tephra' passed into scientific Latin/Neo-Latin as 'tephra' and was adopted into English in the early 19th century as a technical geological term.

Initially, it meant 'ash' in Greek, but over time it evolved into its current scientific meaning of 'fragmental material produced by a volcanic eruption (ash, lapilli, bombs).'