Ar·ca·di·an [aar káydee ?n] adjective 1. ar·ca·di·anof imagined Arcadia: relating to the perfect life of rustic simplicity of Arcadia 2. of Arcadia in Greece: relating to the region of Arcadia in southwestern Greece 3. of Arcadia in California: relating to the city of Arcadia in southwestern California -Ar·ca·di·an, noun