Duh! Even a n00b should know this one. Unless you are Amish, you probably have a bunch of these in your house. Look at the on/off switch on your computer, monitor, or consumer electronic device. Also, try looking near the DC connection on many portable electronics (CD players). If you can't figure it out by now you are hopeless. It is the international symbol for power. What kind of power? That is left up to your imagination. BTW, this shirt is glow in the dark. Also, those of you who pretend to push the button, it does not "turn me on."