Is black wire always live?

I'm curious, is it a universal rule that black wires are always live in electrical systems? I've heard some conflicting information and I'm wondering if there's a definitive answer. Could the color of the wire depend on the specific electrical code or standards in different regions or countries? And if black wires aren't always live, what other factors might determine whether a wire is live or not? I'm eager to learn more about this aspect of electrical wiring.