Webster's Revised Unabridged Dictionary · 1913

Tanak

Tanak (tȧ*nȧk") , noun

[From the initial (Hebrew) letters of Torah, Nevi'im, and Kethubim.]

Although Christians use the term “Old Testament”, this term implies the superseding force of the “New Testament”, not recognized as revelation by the Jewish faith.

A term used among Jews for the Hebrew Bible; the Old Testament.
Old Testament
New Testament
The Hebrew Bible is divided into three parts: (1) The Torah, “Law,” or Pentateuch. (2) The Prophets... (3) The Kethubim, or the “Writings,” generally termed Hagiographa. — C. H. H. Wright

Also: Tanakh