'achates' originates from Latin, specifically the word 'Achates', which was the name of a faithful companion of Aeneas in Virgil's 'Aeneid'.

'Achates' was used in Latin literature and eventually became a term in English to describe a loyal friend.

Initially, it referred to the character 'Achates' in 'Aeneid', but over time it evolved into its current meaning of 'a faithful friend or companion'.