Testament

occurs twelve times in the New Testament (Heb. 9:15, etc.) as
the rendering of the Gr. diatheke, which is twenty times
rendered "covenant" in the Authorized Version, and always so in
the Revised Version. The Vulgate translates incorrectly by
testamentum, whence the names "Old" and "New Testament," by
which we now designate the two sections into which the Bible is
divided. (See BIBLE T0000580.)