What best describes the legal process known as 'joinder'?

Joinder refers specifically to the legal process of adding additional parties to an ongoing lawsuit when those parties are relevant to the dispute at hand. This enables the court to resolve all related matters in a single legal proceeding rather than requiring separate lawsuits for each party, which can be more efficient and promote fairness.

By allowing relevant parties to be added to the case, joinder helps ensure that all necessary parties are present to litigate the issues and that the court can deliver a complete resolution. This principle reflects the aims of procedural efficiency and the interest of judicial economy, as it prevents the necessity for multiple trials addressing the same underlying issue.

Other aspects of the judicial process, such as combining multiple trials, transferring cases, or determining the admissibility of evidence, do not capture the specific function and purpose of joinder in litigation. They address different procedural objectives and are part of broader court management strategies. Therefore, the essence of joinder is best encapsulated by the notion of incorporating relevant parties into one cohesive legal action.