This word occurs 18 times in the Qur'an. Torah be'al peh refers to the traditions that were passed down over the centuries and eventually written down into the mishnah and the gemarah (talmud))
Notice that the Torah and the Injil was called "The Book" and was sent down to the two parties before Muhammad, while the Qur'an was called "a Book" in the above verse.
In al-Fatir 35:31, it is said that the Qur'an was nothing more than a revelation from the previous book. Muslims, however, take this to mean the Mother of Book.