King Ferry Juvenile Law Lawyer, New York

To intentionally destroy, obliterate or strike out records or information in files, computers and other depositories. For example, state law may allow the criminal records of a juvenile offender to be expunged when he reaches the age of majority, to allow him to begin his adult life with a clean record. Or, a company or government agency may routinely expunge out-of-date records to save storage space.

A formal investigation -- governed by court rules -- that is conducted before trial. Discovery allows one party to question other parties, and sometimes witnesses. It also allows one party to force the others to produce requested documents or other physical evidence. The most common types of discovery are interrogatories, consisting of written questions the other party must answer under penalty of perjury, and depositions, which involve an in-person session at which one party to a lawsuit has the opportunity to ask oral questions of the other party or her witnesses under oath while a written transcript is made by a court reporter. Other types of pretrial discovery consist of written requests to produce documents and requests for admissions, by which one party asks the other to admit or deny key facts in the case. One major purpose of discovery is to assess the strength or weakness of an opponent's case, with the idea of opening settlement talks. Another is to gather information to use at trial. Discovery is also present in criminal cases, in which by law the prosecutor must turn over to the defense any witness statements and any evidence that might tend to exonerate the defendant. Depending on the rules of the court, the defendant may also be obliged to share evidence with the prosecutor.

(1) To discredit. To impeach a witness' credibility, for example, is to show that the witness is not believable. A witness may be impeached by showing that he has made statements that are inconsistent with his present testimony, or that he has a reputation for not being a truthful person. (2) The process of charging a public official, such as the President or a federal judge, with a crime or misconduct and removing the official from office.

Circumstances that increase the seriousness or outrageousness of a given crime, and that in turn increase the wrongdoer's penalty or punishment. For example, the crime of aggravated assault is a physical attack made worse because it is committed with a dangerous weapon, results in severe bodily injury or is made in conjunction with another serious crime. Aggravated assault is usually considered a felony, punishable by a prison sentence.

A party's job of convincing the decisionmaker in a trial that the party's version of the facts is true. In a civil trial, it means that the plaintiff must convince the judge or jury 'by a preponderance of the evidence' that the plaintiff's version is true -- that is, over 50% of the believable evidence is in the plaintiff's favor. In a criminal case, because a person's liberty is at stake, the government has a harder job, and must convince the judge or jury beyond a reasonable doubt that the defendant is guilty.

The well-known term for an Alien Registration Receipt Card. This plastic photo identification card is given to individuals who are legal permanent residents of the United States. It serves as a U.S. entry document in place of a visa, enabling permanent residents to return to the United States after temporary absences. The key characteristic of a green card is that it allows the holder to live permanently in the United States. Unless you abandon your residence or violate certain criminal or immigration laws, your green card can never be taken away. Possession of a green card also allows you to work in the United States legally. Those who hold green cards for a certain length of time may eventually apply for U.S. citizenship. Green cards have an expiration date of ten years from issuance. This does not mean that your permanent resident status expires. You must simply apply for a new card.

A method of paying a lawyer for legal representation by which, instead of an hourly or per job fee, the lawyer receives a percentage of the money her client obtains after settling or winning the case. Often contingency fee agreements -- which are most commonly used in personal injury cases -- award the successful lawyer between 20% and 50% of the amount recovered. Lawyers representing defendants charged with crimes may not charge contingency fees. In most states, contingency fee agreements must be in writing.

An order signed by a judge that directs owners of private property to allow the police to enter and search for items named in the warrant. The judge won't issue the warrant unless she has been convinced that there is probable cause for the search -- that reliable evidence shows that it's more likely than not that a crime has occurred and that the items sought by the police are connected with it and will be found at the location named in the warrant. In limited situations the police may search without a warrant, but they cannot use what they find at trial if the defense can show that there was no probable cause for the search.

A term lawyers use to describe the courts and other bureaucracies that handle American's criminal legal business, including offices of various state and federal prosecutors and public defenders. Many people caught up in this system refer to it by less flattering names.