'anorthite' originates from New Latin, ultimately from Greek 'anorthos' (ἀνόρθως) where the prefix 'a-' meant 'not' and 'orthos' meant 'straight' or 'correct'; the mineral name uses the suffix '-ite' typical for minerals.

'anorthite' was formed in New Latin/modern scientific nomenclature from the Greek root 'anorthos' combined with the mineral-forming suffix '-ite' and was adopted into English as the technical mineral name 'anorthite'.

Initially the Greek root conveyed the idea 'not straight' or 'upturned', but in modern usage the term 'anorthite' designates a specific calcium-rich feldspar mineral rather than that abstract literal sense.