🔼The name Arab in the Bible
There are two completely different Hebrew names in the Bible that unfortunately both end up as Arab in English. One is the ethnonym ערב ('arab), which denotes someone from Arabia. Please see our article on that name for its meaning and etymology.
The other name Arab is spelled ארב ('arab), and that name belongs to a city that came to be in the territory of Judah (Joshua 15:52). It's mentioned only once and we don't know anything else about this place, except perhaps that king David's mighty-man Paarai the Arbite may have come from it (2 Samuel 23:35).
🔼Etymology of the name Arab
This name Arab — as spelled with an א (aleph), so that's not an Arab from Arabia — comes from the verb ארב ('arab), meaning to lie in wait or ambush:
For a meaning of this name Arab, NOBSE Study Bible Name List reads A Court, for inexplicable reasons. Jones' Dictionary of Old Testament Proper Names proposes a more logical Ambush. BDB Theological Dictionary does not offer a translation of our name but does list it under the verb ארב ('arab), meaning to lay in wait or ambush.