1: of, relating to, consisting of, or arranged in a series, rank, or row <serial order> 2: appearing in successive parts or numbers <a serial story> 3: belonging to a series maturing periodically rather than on a single date <serial bonds> 4: of, relating to, or being music based on a series of tones in a chosen pattern without regard for traditional tonality 5 a: performing a series of similar acts over a period of time <a serial killer>b: occurring in or involving such a series <a serial murder> 6: relating to or being a connection in a computer system in which the bits of a byte are transmitted sequentially over a single wire — compare parallel