An Acronym for Complex Instruction Set Computing (or chip?)

Describes a CPU that has a large number of machine level instructions hard-coded into it. The most well-known example is the Intel x86 family - each revision has introduced new instructions (for example, MMX extensions) so that the number of instructions in the chip is now well over several hundred.

Compare with RISC (R = reduced)

See for a more in-depth discussion.