The word "Bible" means "the book." In both the Latin and Greek languages the term "Biblia" is a plural noun and signifies "The Books." Originally, the Bible was not one book but a collection of books - in fact, a whole library. It was only in about the fourth century that the seventy two books of the Bible were combined to form the "volume." Eventually, the plural "Biblia" became a singular noun, and in modern languages signifies "the book." The passing of the word "Biblia" from the plural into the singular was no doubt occasioned by an understanding of the real character of the Bible: While the human authors were many, the Divine Author is but one. The Bible is called "The Scriptures" (2 Peter 3:16) and "Holy Scriptures" (Romans 1:2).
Material taken from http://www.cathtruth.com/catholicbible/bookbook.htm