if orthodox is Judaism why is it a form of Christianity?

trying to learn about religion but the pieces are not fitting!

there are orthodox Jews and orthodox Christians. they're denominations

orthodox means adhering to the religious laws
it can be applied to many things

Orthodox is a word used to describe a form of religion, or behavior, and is not exclusive to any individual religion.

The Eastern orthodox catholic church is a branch of Catholicism.
The Hassidic Jews are an ultra-orthodox form of Judaism.

Orthodox Judaism's central belief is that Torah, including the Oral Law, was given directly from God to Moses and applies in all times and places. Orthodox Judaism is not Christianity.

You are confusing two religions. Orthodox Judaism is more conservative form of Judaism, but it is Judaism. Orthodox Christianity refers to the eastern rite Catholics. There are some 24 eastern rite Catholic churches each with their own head. The western rite Catholic Church is called the Roman Catholic Church with its head being the Pope.

There are Orthodox Jews. There are Orthodox Christians.

I am not a Jew so I cannot answer the critical differences between Orthodox and other Jews, but I can tell you about Orthodox Christianity.

Way back at the beginning of Christianity -- Christ was crucified, died and was buried. On the third day he rose again. He had apostles he presented himself to, alive again. Those apostles then went around that part of the world and preached the word of God, and the death and resurrection of Jesus. The most famous is St. Peter, whom Jesus handed his church to, and told him to build this church. Peter became the first Bishop of Rome and founded the Roman Catholic Church. A few hundred years later the first Christian "schism" occurred, and the descendants of the other Christian Churches -- established by the other apostles, had doctrinal arguments. We are all still in the "Fullness of Truth" all of us, and that's the most important thing. These arguments are important between our denominations, but not nearly as critical as the Protestant reformation and it's resulting horror.

So essentially, what I am trying to say is this: Orthodox Christianity has been around since the time of Christ, is in "The Fullness of Truth" in accordance to Christ's teaching. Just as the Roman Catholics are. They are by far, without a doubt, the only "Apostolic succession churches" besides the Roman Catholic Church.

"Orthodox" comes from two Greek words, "or tho" - correct or right, and "docs" - worship or glory.

It has come to mean "standard, accepted methods or teaching", but has the underlying meaning of "correct worship".

There are Orthodox Christians -- members of the Holy Orthodox Catholic and Apostolic Church, and Orthodox Jews. Both hold to very old and little-changing worship pattern and teachings.

Blessings.
/Orthodox (Christian)