Occurs twelve times in the New Testament (Hebrews 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.)

Noah Webster's New International Dictionary of the English Language

1. (n.) A will or covenant; a solemn, authentic instrument in writing, by which a person declares his will as to disposal of his estate and effects after his death.

2. (n.) One of the two distinct revelations of God's purposes toward man; a covenant; also, one of the two general divisions of the canonical books of the sacred Scriptures, in which the covenants are respectively revealed; as, the Old Testament; the New Testament; -- often limited, in colloquial language, to the latter.