In Christianity, the Old Testament is the name of the first part of the Bible which was completed before Jesus Christ was born. Scholars prefer the term Hebrew Bible.
Tertullian was probably the first person to call these books the "Old Testament." He used the Latin name vetus testamentum in the 2nd century.
The collection contains different texts, called "books", about God, and the people of Israel. It can be divided into several sections: the Torah, the History of Israel, the Prophets and Wisdom books. In Judaism, this collection of books is known as Tanakh because it is divided into three parts (Torah, Nevi'im and Ketuvim). Most Jews and many Christians believe these texts to be holy. According to them, God inspired people to write them.
Different religious communities include (or leave out) certain books from the Old Testament. The Catholic Church uses Saint Jerome's Latin translation of the Old Testament called Vulgate. The Eastern Orthodox church uses the ancient Greek translation of Jewish sacred writings called the Septuagint. The Eastern Orthodox list of sacred books has a few more books than the Roman Catholic list. Protestant Bibles stick more closely to the books in the Tanakh but list them in a different order.