What is the difference between santo and sagrado in translating the English religious word "holy." How are the two words used in religious contexts in Spanish-speaking countries?
Holy means sagrado and santo in the sense of sacred:
Holy Land : Tierra santa
Holy Spirit : Espíritu santo
Holy Bible : la santa biblia (common) or la sagrada biblia (uncommon)
Holy Family : la sagrada familia (as in Gaudí's masterpiece)
Holy Grial : el santo grial
It's also translated as bendito(a):
Holy water : agua bendita
However, santo is the word used for a saint:
Saint Patrick : San Patricio. Patricio es un santo.
Saint Mary : Santa María. María es una santa.
All Saints' Day : día de todos los santos.