i386 - This is the first real 32 bit mode 8086 family CPU, 486, Pentiums etc all run 386 code.

IA32 and IA64 are Itanium modes

AMD64, AMD was the first to extend the 386 to 64 bits rather where as Intel was going down the Itanium route

x86_64 is Intel's take on 64 bit version of the 386, playing catchup to AMD

bin refers to binary as in compiled code

src refers to source, as in source code