'argonautic' originates from Greek, specifically the word 'Argonautēs', where 'Argo' was the name of the ship and 'nautēs' meant 'sailor'.

'Argonautēs' passed into Latin as 'Argonauta' and into Late/Medieval Latin as 'argonauticus', which entered English (via French/Latin influences) and eventually became the modern English word 'argonautic'.

Initially it meant 'a sailor of the Argo' or 'relating to the Argonauts', but over time it broadened to mean 'relating to adventurous sea voyages or things reminiscent of the Argonauts'.