This word has been intermingled with the words 'Israelite', 'Judahite', 'Judean', 'pharisee', and 'Edomite' for over 400 years. It's use in the Bible is ambiguous and unfortunately needs to be deciphered for every verse that it is used. Some times it refers to the Roman province of Judea, other times it refers more accurately to Edomites. Other times it references 'Israelites". As an example, I recently reviewed Acts 10:22. It reads from the KJV as:

22 And they said, Cornelius the centurion, a just man, and one that feareth God, and of good report among [G5239] all [G3650] the nation [G1484] of the Jews, [G2453] was warned from God by an holy angel to send for thee into his house, and to hear words of thee.

Properly etymological deliberation and discernment would have this verse read:

22 And they said, Cornelius the centurion, a just man, and one that feareth God, and of good report by1 all2 the Israelites3 of Judea4, was warned from God by an holy angel to send for thee into his house, and to hear words of thee.

The Greek word used here is ‘hypo’ which means - under, i.e. (with the genitive case) of place (beneath), or with verbs (the agency or means, through); (with the accusative case) of place (whither (underneath) or where (below) or time (when (at)):—among, by, from, in, of, under, with.

Footnotes for the numerals above are provided below.

1. The Greek word used here is ‘hypo’ which means - under, i.e. (with the genitive case) of place (beneath), or with verbs (the agency or means, through); (with the accusative case) of place (whither (underneath) or where (below) or time (when (at)):—among, by, from, in, of, under, with.

2. The Greek word ‘holos’ is used, which means – ‘all’, ‘whole’, ‘completely’.

3. Strong’s Concordance defines ‘nation’ (G1484) from the Greek word ‘ethnos’ probably from ‘ethos’ (G1486); which is a race (as of the same habit), i.e. a tribe. The English word ‘ethnic’ certainly better fits the definition as to ‘gentile’, which infers the word ‘goy’; ‘foreigner’; and ‘heathen’. Here, it is referenced as being of the same company; customs and ethnicity. It is therefore "Israelites of Judea" being described here.

4. The Greek word for Jews (G2453) is ‘ioudaios’. This is an adjective descriptive of, but is more properly referenced to the Israelites living in Judea.

The word Jew is an English word originally referring to those Eastern European people who spoke Yiddish. Even the Yiddish people did not view themselves as Israelites. The word 'Jew' did not exist during the Roman times. Rome referred to the region as 'Judea' and those people of the region as 'Judeans'. Even Pontius Pilate inscribed a title in Latin on the torture stake that read - "Jesus the Nazerene King of the Judeans". Every ancient historian, including Josephus referred the region as a greatly mixed population. This makes sense, since the region is indeed at the cross road of trade between three continents. It is also for this reason that there has been constant upheaval of wars. The cross road of trade has always been highly coveted. The entire population of the region has been replaced several times over. Whenever it was conquered, its people were enslaved and carried away in captivity. The allies of the conquering army were rewarded with much of the spoils. By the time the Greeks conquered the region, the people inhabiting the region was vastly populated by the conquering aliens and allies. We know from history that one of the allies, who were instrumental for the conquest of Judah by Nebuchadnezzar, king of Babylon, were the Edomites. They were rewarded by given the lands of the region. This included the shops, businesses, orchards, homes, and more. It is no coincidence that the ancient Greeks prior to the Romans called the region 'Idumea' meaning land of the Edomites. King Herod himself was an Edomite. One doesn't rise to power of a king unless there is an ethnic kinship representing those people. Then we have this from the Jewish Encyclopedia, 1925 edition, Vol. 5, Page 41, which states -- "Edom is in modern Jewry".

As mentioned above, the word Jew derives from a 16th Century Old English mis-transliteration of Yiddish. It stuck. This information is derived from English etymology. The name Jew is analogous to the English appellative name "German" that refers to the people of Deutschland. The people of Deutschland (Germany) call themselves "Deutsch" (the people; race) or 'teuto' as in 'Teutonic' as they were called by the Gallic or 'Tuatha De Dannan', which means 'race or people of Dan'. Obviously, the Deutsch do not call themselves 'Germans'. Another example to the gross misappellation is the name -- 'Welsh'. This is an English word deriving from High German 'wallische' meaning 'strangers'. How utterly absurd for the alien German Angles to call the aborigine Brit population 'strangers'. The 'Welsh' call themselves among each other 'Khumri'. The Jews do not refer to themselves as Israelites. In the 1980 Jewish Almanac, 1st chapter "Identity Crisis" and also found in the Jewish Encyclopedia IV, 1902, p 335), it states -- "Strictly speaking, it is incorrect to call an ancient Israelite a 'Jew' or to call a contemporary Jew an 'Israelite' or a 'Hebrew'".

Most Christians don't realize Judaism is a newer religion than Christianity is and Christianity has NEVER been based on Judaism. This is a inconvenient truth that is publicly a taboo subject. Believe it or not, Judaism was created to confront the spread of Christianity - using the Bible as a prop and also to conceal Judaism's ritualistic practice of blood-letting. The proof is of course in writing and can be found in Judaism's foundational Passover text.

Judaism's foundational Passover text is not from the Old Testament but rather the Haggadah, a thoroughly Talmudic work. (M. Hoffman III, "Judaism Discovered"). The Talmud was compiled as a result of the absolute destruction of Herod’s temple, in which every stone was carried away leaving no trace of it’s existence. In it we learn:

In 66 CE, when the Roman general Vespasian swept into Jerusalem, Judaism was a cultic, oral religion, with Herod's massive temple as its lodestar. Everything happened in the temple complex. Four years later, Vespasian's son Titus razed it to the ground. A quote from the Talmud:

"Where was God under the rubble?" wondered the Rabbis. "How to praise him now that the temple was gone?" The sages agreed: Jews would have to BECOME a people of the book, or they would disappear.

Hence, they were NOT a people of the book before this time.