Defined as: a person who is not Jewish.
From Adam to Noah, some 1600 plus years, there is no distinction between the peoples.
After the Flood, Noah’s decedents were instructed to spread out and repopulate the earth Genesis 9:1.
As they multiplied, Nations were formed, Genesis 10:5, but they were all of one speech and one language, Genesis 11:1. They turned their backs on God and they build a city and tower to make a name for themselves: Genesis 11:1-4. So, God scattered them and confounded their language Genesis 11:7-8. Still no Jews. Then God chose one man, Abram a Hebrew, Genesis 12:1-3, and gave him many promises. After many years Abram was renamed Abraham, Genesis 17:5, and Sarai became Sarah Genesis 17:15. Again years passed and they had a son, Isaac Genesis 21:3. Still no Jew. Isaac took Rebekah to wife Genesis 24:67. They had twin boys, Esau and Jacob Genesis 25:26. Esau married, had sons who became the nation Edom Genesis 36:1. (Not Jews). Jacob married and fathered 12 sons Genesis 35:22. Jacob is renamed (by God) Israel Genesis 32:28. The twelve sons of Jacob (Israel) go into Egypt and under the leadership of Joseph prosper and multiply becoming a nation. 400 years later they are slaves of Egypt. God sends Moses to take them out and lead them to the promise land Genesis 12:7. But just when did they become Jews?
NOTE: The English term Jew originates in the Biblical Hebrew word Yehudi, meaning “from the Kingdom of Judah”.
The first mention of JEW is in 2 Kings 16:6. It would appear, as they occupied the promise land and grew as a nation, the descendants of Abram, a Hebrew, started to call themselves JEWS. The promises God gave to Abram were passed unto Isaac and then to Jacob and his 12 sons who became the nation of Israel, JEWS. Now, anyone descending from any of the twelve tribes (sons of Israel) are called Jews. The rest of the people of the world are Gentiles.
One can follow to Jews all thru history by reading the Bible. From Genesis to Acts, chapter 12, when God shuts the door to Salvation to the Nation of Israel, and opens the door of salvation to the Gentiles, who are spread all over the earth Genesis 11:7-8. This includes Europe, Asia, and the Americas. But as the gentiles traveled, they took with them their false gods and false religious practices. Remember the Tower of Babel Genesis 11:1-4? These towers, pyramids are still being discovered in many parts of the earth.
Why did God exclude the Gentiles until He called Saul (Paul) to go to them with the Gospel? The answer is found in Romans 1:18-32. But now, the door of salvation is open to every individual, Jew and Gentile. Romans 1:13-17.
For more about who are Jews, See God of Abraham, Isaac, Jacob
For more about the tower, See Tower of Babel