A more thorough explanation:

Definition: To set aside or void something, such as a motion or evidence.

Example: The defense attorney filed a motion to quash the subpoena for his client's medical records.

Illustrative caselaw: In Arizona v. Evans, the Supreme Court quashed the defendant's conviction because the evidence used against him was obtained through a clerical error.

Explanation: The term "quash" is often used in legal proceedings to refer to the act of setting aside or voiding something. In the example given, the defense attorney is attempting to quash the subpoena for his client's medical records, meaning he wants to have it declared invalid or nullified. The illustrative caselaw shows how the Supreme Court used the power to quash evidence that was obtained through a mistake, which resulted in the defendant's conviction being overturned.