[asark]

In political science, the nation state is commonly understood as a (relatively) recent development and not a feature of medieval Europe. 15th century Spain is sometimes given as one of the first big steps toward the modern nation state, though it would take some time (centuries) for the phenomenon to spread and to develop into something like its modern form. Like anything there's not 100% agreement over where the boundaries are et c., but in common usage and ordinary context, that's what's typically meant. If you're using it some other way you'll be misunderstood unless you define your terms.