A nation and an ethnoreligious group, originating with the Israelites or Hebrews of the Ancient Near East. Jewish people live in almost every country, as a result of the diaspora.
Questions tagged with jews should refer to people with Jewish ethnicity or with the Jewish religion. Questions about the ethnicity/religion itself should be tagged judaism.
To refer to the ancient Roman Empire provinces of Iudaea or Palestina, consider using palestine along with roman-empire.
For the genocide of Jewish people during the ww2 use the holocaust tag.
For the modern-day state of Israel, it is more appropriate to use israel or palestine, depending on the question's focus.