Christmas Eve
Specifically refers to the night of December 24th, often used in a festive or romantic context. Compare with クリスマスイブ, which is more common in everyday speech.
See also: クリスマスイブ
Many people go to church on Christmas Eve.
holy night
A more general or literary term for a sacred night, not limited to Christmas. Can be used in religious or poetic contexts.
The stillness of the holy night touches my heart.