Adjournment sine die (from the Latin, "without day") occurs when an organized body's existence terminates.
It is often used with regard to legislative bodies whose terms or mandates are coming to an end, as in "The One Hundred Third General Assembly of the State of Georgia closed its second session today by adjourning sine die." This would mean that it is anticipated that this particular body will not meet again; the next session of the legislature would have a somewhat different membership, as some members would not be standing for election again, while others might not win their seats back. However, a legislative body may be called back into special session.
A court may also adjourn a matter sine die, which means the matter is stayed permanently. This may be due to various reasons, for example if the case is started with a wrong procedure chosen the judge may adjourn the matter sine die so that the party may choose to start the action again with the correct procedure.
Another sense of the term, often used by lawyers, does not connote permanent adjournment. When a deposition, for example, is adjourned sine die, it means that no date has yet been set for its resumption, not that it will never be resumed. In fact, it implies that a new date will be set.
The common pronunciation of sine die in the United States Congress is "SEE-nei DEE-ei".
Adjournment sine die is an adjournment until the next session of Congress, there being two sessions to each numbered Congress (e.g. 110th Congress—encompassing the years 2007 and 2008). This is as opposed to an adjournment to a date certain, which occurs periodically during the year. Sine Die adjournments in the U.S. Congress typically do not have a date certain, but rather to be determined by the Speaker of the House and Majority Leader of the Senate at a later time.