Bits...

[kharmini91]

64-bit AMD Processor, 32-bit Windows, 512-bit encryption, 8 bits in a byte, etc.

What exactly is a bit, I think it has to do with graphics, but then a bit is one digit of binary, right? So confusing.....

 

[Horatio]

A bit is one digit of binary. Data, such as graphics, are stored using binary. A 64-bit processor deals with 64 binary digits at a time.

 

[Praetor]

A 64-bit processor deals with 64 binary digits at a time.

Not quite; there's a technicality but its an important one (sort of) and because of it, we have had 64bit processors for a loooooooooong time (i.e., 486 Overdrive, Pentium, etc). That technicality is how you define "64bit cpu" -- if you simply define it as "has support for 64bit operations" or "has support for accepting/manipulating 64bit data" etc then you definitely include those ancient chips because those older chips had a 64bit internal data structure ... now what the Itanium/Itanium2/Opteron/Athlon64 etc have is a 64bit internal and 64bit external data connect ... heehee gotta love those technicalities. A couple of history books:
http://members.iweb.net.au/~pstorr/pcbook/book1/process.htm
http://members.iweb.net.au/~pstorr/pcbook/book1/morehist.htm