It is the set of standards for smartphones and similar devices to establish radio communication with each other by touching them together or bringing them into proximity, usually no more than a few centimeters..
smartphone are no longer just fancy mobile devices that let you e-mail and surf the web. A contemporary smartphone has more power than all of the computers that were at NASA's disposal back in 1969 when the United States first landed on the moon. Although you probably won't use your phone to control your own lunar anytime soon, it will do all sorts of other nifty stuff, like replace your wallet, thanks to NFC(near-field communication) technology.
