I guess you could say that from the time of Jacob (named Israel) forward... anyone not in that lineage would be considered a Gentile.
Big thanks for your reply. I remember that Jacob took a wife from among the Gentiles.
Maybe the start of them just isn't in the bible.
But, see, before Jacob (or arguably more specifically, before Abraham), everyone
was a Gentile. Or, maybe more accurately, there were neither Jews nor Gentiles. There were just the people who lived back then who were the ancestors of the Jews and Gentiles.
Gentiles, as is conventionally meant by that term, simply means non-Jewish or non-Hebrew. If we say that Jews are the descendents of Israel/Jacob, then before Jacob, the "Jews" didn't exist.
Of course, the word "Gentiles" only has meaning in the context of there being "Jews." Before the "Jews," there was really neither Jew nor Gentile. There were just people.