What’s the difference between  "contact" and "contactless"  smart card ?

The smart cards chip must have a technology that allows simultaneously the power supply and communication with readers. Some smart cards have gilded plaques, otherwise contacts, positioned in one of the card’s corner: these are called smart cards with contact. When you insert the smart card into a reader, this one sustains its contacts on plaques in order to supply power and communicate with the chip.
Other smart cards do not have connectors on their  own surface and the communication with the reader is realized in Radio Frequency (RF). The chips are pressured in plastics and have a coil shaped antenna.
This type of cards are also called smart card of proximity otherwise without contact or contactless.