Can you tell me why the Bible is called the Bible?

The English word "Bible" comes originally from the byblos reed or papyrus, used in old times for making scrolls and books. In Greek biblos is the word for a small book. Early Christians called the Scriptures "ta Biblia" meaning 'the books', because it was a collection of a number of small books. When it came into English via Latin and French the plural was dropped and it became simply "The Bible". To distinguish it from other books it is often called the "Holy Bible."

Reference: Ungers Bible Dictionary.