Story structure
Story arc
The chronological construction of a plot across a novel, film or episodic media: a story extended over multiple installments instead of one.
A story arc is "the chronological construction of a plot in a novel, film, or episodic media" such as television, comics and video games; in episodic forms an arc "unfolds over multiple episodes or seasons instead of resolving in a single installment." Multi-episode plots are centuries old, but one early print use of the phrase is a 1973 Time review of The Friends of Eddie Coyle. Arcs "move a character or situation from one state to another," often along a familiar pattern such as the tragic fall or the Hero's Journey. American comics are split into four- to six-issue arcs that collect cleanly into trade paperbacks, and long-running series from One Piece to Dragon Ball are built as chains of distinct arcs.
For serial writers the arc is the planning unit: chapters are the beats, arcs are the promise, and a season or book is arcs arranged end to end. Each plot arc bends around a character arc, and stretching arcs across multiple books is the craft of how to write a series.