'astrogeology' originates from modern English combining the Greek-derived prefix 'astro-' (from Greek 'astron') meaning 'star' and the word 'geology' (from Greek 'geōlogia'), where 'geo-' meant 'earth' and '-logy' meant 'study of'.

'geology' derives from Greek 'geōlogia' via Latin and Medieval/Modern English; the compound 'astrogeology' was formed in the 20th century by joining 'astro-' + 'geology' to denote the study of extraterrestrial geological features.

Initially the components meant 'star' and 'study of the Earth', but the combined term evolved to mean specifically the 'study of the geology of celestial bodies' rather than Earth's geology alone.