The story
Found in Plato's dialogue Euthyphro, in which Socrates asks Euthyphro, "Is the pious (τὸ ὅσιον) loved by the gods because it is pious, or is it pious because it is loved by the gods?"
Etymology from Wiktionary, CC BY-SA 4.0.
Euthyphro dilemma
Today it means: A dilemma as to whether things that are morally good are commanded by God because they are morally good, or whether they are morally good because they are God's commands. Full definition →