With Mr Clinton testifying in the Monica Lewinsky sex and perjury scandal, the following is a guide to some of the legal jargon surrounding the investigation:
Grand jury - A group of people (usually 23) drawn from the general population whose purpose is to investigate and inform on crimes and to accuse (or indict) those responsible if and when it has evidence to warrant holding a person for trial.
Perjury - The criminal offence of making false statements under oath.
Subornation of perjury - The crime of inducing another to make a false statement under oath.
Subpoena - A writ issued under the authority of a court to compel the appearance of a witness at a judicial proceeding. Disobeying a subpoena may be punishable as contempt of court.
Affidavit - A written statement made or taken under oath before an officer of the court or a notary public.
Immunity - A guarantee against prosecution or penalty. Immunity is often granted to a witness to compel answers to questions he or she might otherwise refuse to answer on grounds of self-incrimination.
Fifth Amendment/"Taking the Fifth" - The section of the US Constitution, part of the Bill of Rights, that establishes protections for citizens from actions of the government. It provides, among other things, that no one can be required to testify against (or incriminate) himself/herself. Independent Counsel - Independent counsels are assigned to investigate high-level members of the executive branch or those who serve on the election campaigns of presidents.
The first step in their appointment is a decision by the Attorney General that there is credible evidence that someone may have violated serious federal criminal laws and that investigation or prosecution by the Justice Department could result in personal, financial or political conflict of interest because the Attorney General works for the president.
The Attorney General must request an independent counsel who is then chosen by a panel of the US Courts of Appeals for the D.C. Circuit. Although the scope of the independent counsel is limited, there is no limit on the time or money which may be expended.
Obstruction of justice - Impeding or obstructing those who seek justice in a court or those who have the duties or powers of administering justice. It includes such acts as attempting to influence, intimidate or impede a juror, witness or officer of any court.
Deposition - A pretrial statement by a witness under oath in question-and-answer form as it would be in court. When a witness is "deposed", the adversary can be present and cross-examine.