Though the terms "Bible" and "Old Testament" are commonly used by non-Jews to describe Judaism's scriptures, the appropriate term is "Tanach," which is derived as an acronym from the Hebrew letters of its three components: Torah, Nevi'im and Ketuvim.
Torah - Pentateuch
Navi - Prophets
Ketuvim - Writings
Sources: Jewish Publication Society, 1917, from the Jewish Bible