'Argulus' originates from New Latin, specifically the genus name 'Argulus' coined in zoological taxonomy (a modern Latin formation), where the name was taken as a taxonomic label for these parasitic crustaceans.

'Argulus' was adopted into scientific (New Latin) usage in zoology as the established genus name for fish lice and entered modern English usage unchanged as the taxonomic term 'Argulus' and its anglicized plural forms.

Initially coined as a scientific genus name for certain parasitic crustaceans, the term has retained that specialized biological meaning in modern usage.