I think we used to call them folk songs but people who sang folk songs ended up singing anything, so some other people used the word 'traditional' to label songs that were mostly (1) old, (2) anonymous (3) passed through an oral rather than a written tradition, (4) changed through time. Not all 4 are always proven or in equal measure but these criteria do identify songs & music that are different from Art music which is usually the opposite.

Traditional stuff does usually sound different. Its strange emotional affect is often enhanced when sung or played by someone who has learned the song from within that oral tradition. It affects us in some emotional way that Art music does not. Not better, not worse but different.