war: open armed conflict between opposing forces, and by extension a single battle or even fierce fighting among people.
The word covers the whole span of organized hostility, from a drawn-out war between peoples down to a single clash on the battlefield. In the Gospels it appears in the plural in Jesus' warning about "wars and rumors of wars," where it names war as a recurring feature of history rather than any one conflict.
More often in the New Testament it narrows to a specific battle or armed engagement: a king weighing whether to meet another king in the field, a trumpet call summoning soldiers to the fight, and above all the run of decisive clashes in Revelation, from the war in heaven to the final gathering of the nations.
Once it turns inward. When James asks where the "wars and fights" among believers come from, he is not describing armies but the quarreling and rivalry that tear a community apart, pairing it with μάχη, the word for a personal fight or dispute.