Where does “Μακεδονία” come from?

Μακεδονία (Ancient Greek) comes from Ancient Greek μακεδονία, from Ancient Greek μακεδνός, from Ancient Greek μακρός, from Proto-Italic makros, from Proto-Indo-European mh₂ḱrós, from Proto-Indo-European meh₂ḱ- — to raise, increase; long.

Μακεδονία (Ancient Greek): Macedonia