A legislative session is the period of time in which a legislature, in both parliamentary and presidential systems, is convened for purpose of lawmaking, usually being one of two or more smaller divisions of the entire time between two elections. In each country the procedures for opening, ending, and in between sessions differs slightly. A session may last for the full term of the legislature or the term may consist of a number of sessions. These may be of fixed duration, such as a year, or may be used as a parliamentary procedural device. A session of the legislature is brought to an end by an official act of prorogation. In either event, the effect of prorogation is generally the clearing of all outstanding matters before the legislature.
Historically, each session of a parliament would last less than one year, ceasing with a prorogation during which legislators could return to their constituencies. In more recent times, development in transportation technology has permitted these individuals to journey with greater ease and frequency from the legislative capital to their respective electoral districts (sometimes called ridings) for short periods, meaning that parliamentary sessions typically last for more than one year, though the length of sessions varies. Legislatures plan their business within a legislative calendar, which lays out how bills will proceed before a session ceases, although related but unofficial affairs may be conducted by legislators outside a session or during a session on days in which parliament is not meeting.
While a parliament is prorogued, between two legislative sessions, the legislature is still constituted – i.e. no general election takes place and all Members of Parliament thus retain their seats. In many legislatures, prorogation causes all orders of the body – bills, motions, etc. – to be expunged. Prorogations should thus not be confused with recesses, adjournments, or holiday breaks from legislation, after which bills can resume exactly where they left off. In the United Kingdom, however, the practice of terminating all bills upon prorogation has slightly altered; public bills may be carried over from one legislative session to the next.