The terms "Old Testament" and "New Testament" refer to two distinct collections of sacred texts within the Bible, and the word "testament" is used to describe a covenant, agreement, or pact. This usage stems from the translation of Greek words like "diatheke" (διαθήκη), which meant both "covenant" and "will," and the Latin term "testamentum," which was used to translate "diatheke" in early translations. 

Elaboration:

• Greek and Hebrew Origins:

  The Hebrew word "brit" (בְּרִית) and the Greek word "diatheke" (διαθήκη) both mean "covenant" or "agreement," not "will" in the modern sense of a legal document for inheritance. 

• Translation History:

  When the Hebrew Bible (Old Testament) was translated into Greek (the Septuagint), "diatheke" was used to translate "brit." Later, when these Greek translations were further translated into Latin, the word "testamentum" was used to represent "diatheke." This led to the English terms "Old Testament" and "New Testament". 

• Meaning of "Testament":

  In the context of the Bible, "testament" signifies a covenant or agreement between God and humanity. It's about a relationship, a promise, and a way of life rather than a legal document. 

• Old Testament:

  This collection of books primarily documents the history and laws of the Israelites, their covenant with God, and their relationship with him. 

• New Testament:

  This collection of books focuses on the life, teachings, death, and resurrection of Jesus Christ, and how his actions fulfilled and extended the covenant established in the Old Testament. 

In essence, the use of "testament" in the Bible is a translation of the Greek and Hebrew words for "covenant," which is a solemn agreement or pact between God and humanity.