Of or pertaining to Delos, a Greek island in the Cyclades, in ancient times regarded as sacred to Apollo.
Delian League an alliance of ancient Greek city states, dominated by Athens, that joined in 478–447 bc against the Persians. The league was disbanded on the defeat of Athens in the Peloponnesian War (-404 bc), but again united under Athens' leadership against Spartan aggression in 377–338 bc. Also called the Athenian empire.
Delian problem the problem of finding geometrically the side of a cube having twice the volume of a given cube (from the Delian oracle's pronouncement that a plague in Athens would cease if the cubical altar to Apollo were doubled in size).