Multitasking - concurrent execution of multiple tasks over a certain period of time. New tasks can interrupt already started ones before they finish, instead of waiting for them to end. As a result, a computer executes segments of multiple tasks in an interleaved manner, while the tasks share common processing resources such as central processing units (CPUs) and main memory.
Superscalar - a computer architecture that loads several instructions at once and executes them simultaneously. Also known as a processor that supports dynamic multiple issues. Also implements a form of parallelism called instruction - level parallelism within a single processor