Jewish people are best described in modern terms as an ethnoreligious group, defining their rules of membership as well as their rules of practice. Modern concepts of ethnicity, religion, and nationality are not entirely sufficient to capture the millennia-long meaning of Jewishness. Being Jewish is a mix of being born into a Jewish community, and of behavior according to the regulations of the community. Judaism is the religious practice of Jewish people.
The word “Judaism” comes from “Judah-ism” and means means “of the people of Judah” — referring to people from the tribe of Judah. This was one of the twelve tribes which constituted the nation when it came into existence. The word "Jewish" comes from "Judah" as well. This is used in many languages, and by Jews, to refer to Jewish people, although other terms exist as well.
The Jewish view is that Jews have a common ancestor: Jacob, and before Jacob, of course, going back to Adam. Jacob's condensed family tree is below, including the twelve tribes of Jacob, who gained the second name Israel. The tree below uses the notation of “personal name” + “ben (son of)” + “father’s personal name” for clarity.
Abraham ben Terah אברהם בן תרח
Abraham was born with the name Abram.
Isaac ben Abraham יצחק בן אברהם
Jacob ben Isaac יעקב בן יצחק
Jacob was given the name Israel by an angel, hence the phrases "Twelve Tribes of Israel" or "Land of Israel" and terms such as "Israelites" among others.
Reuben ben Jacob ראובן בן יעקב
Simeon ben Jacob סימאון בן יעקב
Levi ben Jacob לוי בן יעקב
Judah ben Jacob יהודה בן יעקב
Isacchar ben Jacob איזכר בן יעקב
Zebulun ben Jacob זבולון בן יעקב
Gad ben Jacob גד בן יעקב
Asher ben Jacob אשר בן יעקב
Dan ben Jacob דן בן יעקב
Naphtali ben Jacob נפתלי בן יעקב
Joseph ben Jacob יוסף בן יעקב
Joseph's tribe was split into two 'half tribes' out of respect from his sons, who were each given elevated designation as their own tribes, unlike other grandchildren of Jacob.
Ephraim ben Joseph אפרים בן יוסף
Manasseh ben Joseph מנשה בן יוסף
Benjamin ben Jacob בנימין בן יעקב
"Hebrew" is the language of the Jewish people. It is descended from ancient Aramaic, which was the lingua franca of West Asia in antiquity. The term "Hebrew" is also used to refer to the Jewish people, sometimes. It is etymologically related to words meaning "to cross" — it may refer to Jewish people immigrating, or it may refer to Jewish people standing across from the idolatrous nation. Abraham is sometimes referred to as Abram Ha-Ibri, meaning Abram the Hebrew, before his name was changed to Abraham.