Multicore processor
Beginner
A chip with several complete processors, called cores, side by side. Each core can run its own program at the same time as the others.
Novice
A processor chip with two or more cores, each able to run its own stream of instructions, sharing the chip’s caches, memory connections and power budget. Since the mid-2000s nearly every CPU is multicore.
Expert
Thread-level parallelism on one die: N cores with private L1/L2, a shared last-level cache and interconnect, kept coherent by hardware. It replaced frequency scaling once power, not transistors, became the binding limit.
Explained in Multicore and vector units (Architectures).
See also: Power wall, Amdahl’s law, Last-level cache (LLC).