Abbreviated as CMT, chip multithreading is the capability of a
processor to process
multiple software threads and supports simultaneous hardware threads of
execution. CMT is achieved by having multiple cores on a single chip (to share
chip resources such as, the memory controller and the L2 cache) or multiple
threads on a single core.
Chip Multithreading: Opportunities and Challenges (PDF) Chip Multi-Threaded (CMT) processors provide support for many simultaneous hardware threads of execution in various ways, including Simultaneous Multithreading (SMT) and Chip Multiprocessing (CMP).