I also directed the question to the Jews, isn't the Torah part of the OT?
if it isn't , I hope they answer from whatever book they follow
The term "Old Testament" infers that there is a "New Testament". The New Testament is a distinctly Christian collection of Scripture, and that is why we refer to what came before--the Law and the Prophets--as the "Old Testament".
Judaism has the Tanakh. Which corresponds pretty much completely with the Christian Old Testament, but it's not perfect.
For one, Christians have historically embraced more books than Judaism has--Tobit, Sirach, 1 & 2 Maccabees, Judith, etc. And while Protestants have mostly removed these from our Canon (either formally or informally) they still play an important role in the history and developement of the Christian Old Testament Canon. What books Christians came and embraced as "the Old Testament" was a different historical process than the Jewish process of accepting and embracing the Tanakh, the two processes mostly happened side-by-side historically, but the two were still different because Christianity and Judaism had become distinct and separate religions by the time Christians were working on our Canon and the Jews working on theirs.
While Christians embraced en masse the Law and Prophets, just as Judaism had before, the fiddling around with a third category of texts--the Writings--remained more fluid. Which is why sometimes Christians accepted Esther as Scripture, and sometimes they didn't. Sometimes Christains accepted Sirach, sometimes they didn't. Though Judaism embraces Esther and rejects Sirach.
It is thus rather and technically incorrect to say the Jews have the Old Testament, even though all the books the Jews have in the Tanakh are in the Christian Old Testament and thus the two look just about the same. In particular the Protestant Old Testament is just about identical with the Jewish Tanakh, though Protestants have historically used more sources than the Masoretic Hebrew, we've historically continued to use the Septuagint; which is one fundamental reason why Christian translations and Jewish translations can often differ dramatically at certain points.
I know this. it happened centuries after Jesus. what was the name at his time until the Antioch gathering?
Centuries? Try no more than a decade after Jesus. Christians didn't call themselves anything different while they were a group of men and women following their Rabbi, they called themselves "Jews".
Other names they gave themselves, after the resurrection, was "The Way", and they also called themselves "Disciples" and "Brothers". But the name that really stuck was "Christian", and it's the name we keep encountering following this.
and the word Christian refers to Christ.
The Greek word is "christianos" (singular)/"christianoi" (plural) and just about literally means "Christ person"/"Christ people". It may have originally been a nasty epithet, mocking these weird people speaking of "the oily one" (christos). Whatever the case may be, it's the name that stuck. We are followers of
the Christ, and thus
Christians. We're Jesus People.
-CryptoLutheran
