What is Intel CPU?

Answer 1

I assume you mean an Intel Microprocessor.

Intel has made many different microprocessors, starting with the 4 bit Intel 4004 in 1971 followed by the 8 bit Intel 8008 in 1972.

The modern Intel Microprocessor used in PC is a 32 bit or 64 bit Microprocessor whose architecture is derived from the 8 bit Intel 8008. Some of the other Intel Microprocessor in this path of architectural evolution are the 8 bit Intel 8080, the 8 bit Intel 8085, the 16 bit Intel 8086 (and the 16 bit Intel 8088 with 8 bit external multiplexed databus), the 16 bit Intel 80186, the 16 bit Intel 80286, the 32 bit Intel 80386 (first 80x86 Microprocessor to implement virtual memory), the 32 bit Intel 80489, the 32 bit Intel Pentium (was originally to have been the 80586, but you cannot Trademark numbers only words and Intel wanted a Trademark at that time to protect their IP rights).

Intel also built many other Microprocessors with unrelated architectures (e.g. 3000 series bitslice, 80432, 80860, 80960).