'astrophobia' originates from Greek roots: specifically 'astron' meaning 'star' and 'phobos' meaning 'fear'.

'astrophobia' is a modern English coinage formed from the Greek elements 'astron' and 'phobos' (via New Latin/modern formation) rather than from a single older English word; the combination follows the pattern used to form many scientific and medical terms.

Initially the elements meant 'star' and 'fear' in Greek; the combined modern term has come to mean an irrational fear of stars, celestial bodies, or outer space.