'anorexia' originates from Greek, specifically the word 'anorexia' (Greek ἀνορεξία), where the prefix 'an-' meant 'without' and 'orexis' meant 'appetite' or 'desire'.

'anorexia' entered English via Neo-Latin/medical Latin 'anorexia' and was adopted into English medical usage in the 19th century, becoming the modern English word 'anorexia'.

Initially, it meant 'loss of appetite' in a general sense, but over time it became specialized to refer also to the clinical disorder 'anorexia nervosa'.