[Concurrent (order-independent) vs sequential] There's a set of concurrency-related terms that start with a contraction of the word "multiple": multi-tasking, multi-programming, multi-processing, multi-threading and multi-core. Multi-threading generally means using system threads and multi-core refers to hardware concurrency, but the other terms are ambiguous and can either just mean concurrency in general or something more specific like using system processes or avoiding busy-waiting, so the ambiguous terminology should preferably be avoided.