'astrapophobia' originates from Greek, specifically the word 'astrape' (Greek: ) meaning 'lightning', combined with the Greek element 'phobia' from 'phobos' meaning 'fear'.

'astrapophobia' was formed in modern English as a compound of Greek roots; it is closely related to the variant 'astraphobia' (from Greek 'astrape') and aligns with other English formations using '-phobia' to denote irrational fears.

Initially the root referred specifically to 'lightning'; over time the modern compound has come to denote fear of both lightning and associated thunder (i.e., storms generally).