# [[Serial]] Serial refers to items or tasks that belong in a certain order, usually chronological or sequential. When compared to [[Parallelism|parallel]] elements, serial elements cannot occur simultaneously. For example, a TV *series* is episodic in nature: each show is an installment of a story that proceeds from start to finish. Watching episodes in a series out of sequence would be confusing. In [[Tech|Computer science]], serial processing consists of tasks that must be done in order and cannot be [[Parallelism|parallelized]] due to dependencies on previous tasks in the series. While parallelism is simultaneous, serial processing is sequential.