The "Star of David" is known in
Hebrew as Magen David, which literally means the "shield of David,"
apparently from the popular notion that the Beloved King of Israel wore
this symbol on his shields, although there is no evidence that this is
true.
The symbol was used in Israel in Roman times, but it seems to have
become particularly associated with Judaism only in later centuries.
In the 17th century, it became a popular practice to put the Star of
David on the outside of synagogues, to identify them as Jewish houses
of worship; however, it is not clear why this symbol was selected for
this. Today the Star of David is a universally recognized symbol of
Jews. It appears on the flag of the state of Israel, and the Israeli
equivalent of the Red Cross is known as the Magen David Adom.