A curse is generally understood as a supernatural or spiritual imprecation—a harmful wish or command meant to bring misfortune, suffering, or punishment upon a person, group, object, or place.
The curse of a goddess is far stronger and more powerful than a normal magical imprecation. The ensuing affliction goes beyond the standard laws of magic and the spiritual world when a mortal is cursed by a powerful deity.
Just like what happened with Medusa's curse. Athena's punishment was not just a hex or jinx; it changed Medusa's fundamental nature, giving her a terrifying power that she could hardly control. When Medusa's eyes meet a living being, they are immediately transformed into stone by an uncontrollable magical need.