A Jew is any person whose mother was a Jew.
It is important to note that being a Jew has nothing to do with what you believe or what you do. A person born to non-Jewish parents who has not undergone the formal process of conversion but who believes everything that Orthodox Jews believe and observes every law and custom of Judaism is still a non-Jew, even in the eyes of the most liberal movements of Judaism, and a person born to a Jewish mother who is an atheist and never practices the Jewish religion is still a Jew, even in the eyes of the ultra-Orthodox. In this sense, Judaism is more like a nationality than like other religions, and being Jewish is like a citizenship.
Who Is a Jew?
Level: Basic
Origins of the Words "Jew" and "Judaism"
The original name for the people we now call Jews was Hebrews. The word "Hebrew" (in Hebrew, "Ivri") is first used in the Torah to describe Abraham (Gen. 14:13). The word is apparently derived from the name Eber, one of Abraham's ancestors. Another tradition teaches that the word comes from the word "eyver," which means "the other side," referring to the fact that Abraham came from the other side of the Euphrates, or referring to the fact Abraham was separated from the other nations morally and spiritually.
Another name used for the people is Children of Israel or Israelites, which refers to the fact that the people are descendants of Jacob, who was also called Israel.
The word "Jew" (in Hebrew, "Yehudi") is derived from the name Judah, which was the name of one of Jacob's twelve sons. Judah was the ancestor of one of the tribes of Israel, which was named after him. Likewise, the word Judaism literally means "Judah-ism," that is, the religion of the Yehudim. Other sources, however, say that the word "Yehudim" means "People of G-d," because the first three letters of "Yehudah" are the same as the first three letters of G-d's four-letter name.
Originally, the term Yehudi referred specifically to members of the tribe of Judah, as distinguished from the other tribes of Israel. However, after the death of King Solomon, the nation of Israel was split into two kingdoms: the kingdom of Judah and the kingdom of Israel (I Kings 12; II Chronicles 10). After that time, the word Yehudi could properly be used to describe anyone from the kingdom of Judah, which included the tribes of Judah, Benjamin and Levi, as well as scattered settlements from other tribes. The most obvious biblical example of this usage is in Esther 2:5, where Mordecai is referred to as both a Yehudi and a member of the tribe of Benjamin.
In the 6th century B.C.E., the kingdom of Israel was conquered by Assyria and the ten tribes were exiled from the land (II Kings 17), leaving only the tribes in the kingdom of Judah remaining to carry on Abraham's heritage. These people of the kingdom of Judah were generally known to themselves and to other nations as Yehudim (Jews), and that name continues to be used today.
In common speech, the word "Jew" is used to refer to all of the physical and spiritual descendants of Jacob/Israel, as well as to the patriarchs Abraham and Isaac and their wives, and the word "Judaism" is used to refer to their beliefs. Technically, this usage is inaccurate, just as it is technically inaccurate to use the word "Indian" to refer to the original inhabitants of the Americas. However, this technically inaccurate usage is common both within the Jewish community and outside of it, and is therefore used throughout this site.
Who is a Jew?
A Jew is any person whose mother was a Jew or any person who has gone through the formal process of conversion to Judaism.
It is important to note that being a Jew has nothing to do with what you believe or what you do. A person born to non-Jewish parents who has not undergone the formal process of conversion but who believes everything that Orthodox Jews believe and observes every law and custom of Judaism is still a non-Jew, even in the eyes of the most liberal movements of Judaism, and a person born to a Jewish mother who is an atheist and never practices the Jewish religion is still a Jew, even in the eyes of the ultra-Orthodox. In this sense, Judaism is more like a nationality than like other religions, and being Jewish is like a citizenship. See What Is Judaism?
This has been established since the earliest days of Judaism. In the Torah, you will see many references to "the strangers who dwell among you" or "righteous proselytes" or "righteous strangers." These are various classifications of non-Jews who lived among Jews, adopting some or all of the beliefs and practices of Judaism without going through the formal process of conversion and becoming Jews. Once a person has converted to Judaism, he is not referred to by any special term; he is as much a Jew as anyone born Jewish.
Although all Jewish movements agree on these general principles, there are occasional disputes as to whether a particular individual is a Jew. Most of these disputes fall into one of two categories.
First, traditional Judaism maintains that a person is a Jew if his mother is a Jew, regardless of who his father is. The liberal movements, on the other hand, consider a person to be Jewish if either of his parents was Jewish and the child was raised Jewish. Thus, if the child of a Jewish father and a Christian mother is raised Jewish, the child is a Jew according to the Reform movement, but not according to the Orthodox movement. On the other hand, if the child of a Christian father and a Jewish mother is not raised Jewish, the child is a Jew according to the Orthodox movement, but not according to the Reform movement! The matter becomes even more complicated, because the status of that children's children also comes into question.
Second, the more traditional movements do not always acknowledge the validity of conversions by the more liberal movements. The more modern movements do not always follow the procedures required by the more traditional movements, thereby invalidating the conversion. In addition, Orthodoxy does not accept the authority of Conservative, Reform and Reconstructionist rabbis to perform conversions, and the Conservative movement has debated whether to accept the authority of Reform rabbis.
From jewfaq.org
Of that list of pianist who was orthodox?
Topic: List of Jewish pianists, wow...