Short for multiple instruction, single data. A type of parallel computing architecture that is classified under Flynn's taxonomy. Each processor owns its control unit and its local memory, making them more powerful than those used in SIMD computers. Each processor operates under the control of an instruction stream issued by its control unit: therefore the processors are potentially all executing different programs on different data while solving different sub-problems of a single problem. This means that the processors usually operate asynchronously. [Source: Tommesani]
See also Flynn's taxonomy.