What is the definition of "quash" in a legal setting?

In a legal context, the term "quash" refers to the act of declaring a legal decision or another legal proceeding as invalid, null, or void. When a court quashes a subpoena, for example, it renders that subpoena ineffective and unenforceable. This action often occurs when there are issues such as lack of jurisdiction, violating due process, or when the legal requirements have not been met. Quashing is essentially a means of protecting individuals from unwanted legal actions or ensuring that legal protocols have been correctly followed. Understanding this definition is crucial for legal professionals, as it impacts how cases are managed and how legal documents are treated within the judicial system.