The plugs on some newer appliances have a third round grounding pin. Almost all homes and commercial buildings are equipped with electrical receptacles that can accommodate either type of plug. If you bring any electrical appliance to the USA, you may need an adaptor to fit the US electrical receptacles. You may also need a converter to change the voltage from 110 volts to 220 volts. Most common appliances will function with either 50 or 60 cycle current.
Electrical frequency can affect electric clocks, audio equipment and some other electronic gear.
It may be more convenient and even more economical to buy an inexpensive appliance that is fully compatible with US electrical power.