Question: When was the Bible first referred to as the "Holy" Bible?

Etymology
Main article: Hailag
The word "sacred" descends from the Latin sacrum, which referred to the gods or anything in their power, and to sacer, priest; sanctum, set apart. It was generally conceived spatially, as referring to the area around a temple.

The origin of the word "holy" comes from the 11th Century Old High German hulis and Old English holegn meaning Holly as in Holly Tree, considered a sacred plant to both pre-Christian Celtic and Roman worship. The word hulis originates from an even older proto-Germanic word khuli a shortened derivation of the ancient Gaelic cuilieann both meaning Holly. The distinction of the word holy appeared around the 13th Century with the Old English word hālig derived from hāl meaning health, happiness and wholeness. As “wholeness”, holiness may be taken to indicate a state of religious completeness or perfection.

In non-specialist contexts, the term "holy" is used in a more general way, to refer to someone or something that is associated with a divine power, such as water used for Baptism.