Original: The Song of Songs (Hebrew,, Shir ha-Shirim), is a book of the Hebrew Bible - one of the five megillot (scrolls) - found in the last section of the Tanakh, known as the Ketuvim (or "writings").
Simplified: The Song of Songs is a book of the Hebrew Bible or Tanakh, and also in the Old Testament of the Christian Bible. It is one of the five megillot (scrolls).