A dynasty has two meanings in basketball. On the court, it is a team that wins several championships over a run of years with the same core. In fantasy and sim circles, a dynasty league is one that carries rosters over from season to season instead of starting fresh, so you build for years rather than months.
HoopSim leagues are dynasty leagues by nature: a league keeps going season after season, with the same GMs, contracts that run their course, a lottery and two-round draft, free agency and training camp between seasons, and a history of standings and awards. Building a dynasty on the court means managing the cap (Bird rights, extensions, the tax and the aprons), keeping a core together for chemistry, and drafting and developing well while your stars age. Your Legacy level, which follows you across leagues, rises with playoff runs and titles and never goes down.
Rulebook: The offseason. Related: rebuild, sim league.