'astrochemist' is a modern English compound formed from the prefix 'astro-' (from Greek 'astron' meaning 'star') and 'chemist' (from 'chemistry').

'astro-' derives from Greek 'astron' meaning 'star'; 'chemist' comes via Modern English from 'chemistry', itself from Medieval Latin/Old French forms of Greek/Arabic 'khēmeia'/'al-kīmiyāʾ'. The compound 'astrochemist' emerged in the 20th century alongside the development of the scientific field astrochemistry.

Originally the elements 'astro-' and 'chemist' separately meant 'star' and 'a practitioner of chemistry'; over time the compound came to denote a specialist studying chemical processes in space rather than simply a chemist who studies stars in a lay sense.