Serial versus SPI

Question

What is the difference between SPI and serial? In reading an article talking about inter-processor communications, it states that serial interfaces are being replaced with SPI f

Answer 1

The first answer is almost correct with some small comments:

1) SPI is a subtype of SSI (another example is RS-422)
2) SPI uses the master/slave concept with CS/SS (chips select, slave select) pin ...

Thus a master can have multiple slaves and select between them using the SS pin. Also, on some chips, using the SS the chip can be switched from master to slave.