A little thing that has always been bugging me. Here we have 220 volts by using 2 110 volt legs that are 180 degrees apart. Ie, load on 2 legs. Much of Europe has 220 volts, but only on one leg, the other is neutral. Like our 110V setup, but 220 volts. 3 phase has power on three wires, makes sense to call it 3 phase. Single phase 110V here (or 220V in much of Europe), only has the load on one wire. Again, it makes sense to call in single phase. Following all that, it seems that our 220 Volts (110 on each leg), should be called 2 phase.