'astacus' originates from Latin, specifically the word 'astacus', ultimately from Greek 'ἀστακός' ('astakos'), where the Greek word meant 'lobster' or 'crayfish'.

'astacus' changed from the ancient Greek word 'ἀστακός' and passed into Latin as 'astacus', later used in Medieval and New Latin and finally adopted as the modern scientific genus name 'Astacus'.

Initially, it meant 'lobster' or 'crayfish' in general, and over time it has been retained as the name for a genus of freshwater crayfish in scientific nomenclature.