'Athenian' originates from Greek, specifically the word 'Athenaios', where 'Athenai' meant 'Athens' and the suffix '-ios' meant 'belonging to.'

'Athenaios' passed into Latin as 'Athenaeus' and later into Middle English/Middle French forms before becoming the modern English word 'Athenian'.

Initially, it meant 'belonging to or from the city of Athens'; over time the core meaning has remained but it also acquired the specific historical sense of 'relating to ancient/classical Athens.'