Radio frequency identification (RFID) is a generic term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object or person wirelessly, using radio waves. It's grouped under the broad category of automatic identification technologies.
RFID is in use all around us. If you have ever chipped your pet with an ID tag, used Oyster when travelling in London, you've used RFID. In addition, RFID is increasingly used with biometric technologies for security.
Unlike ubiquitous UPC bar-code technology, RFID technology does not require contact or line of sight for communication. RFID data can be read through the human body, clothing and non-metallic materials.