A regular period of time, as a month, quarter, or year, for which an operative statement is drawn up.

A length of time in which the two sides to a purchase agreement, or contract can think things over and cancel with no penalty. This period is often stipulated by national law. In the UK it is currently (2008) 14 days. In many countries it is 10 days.

A time of warm climate in the North Atlantic region that may have been related to other climate events around the world during that time, and which lasted from about 950 to 1250.

plural of operational service period

(historical) The period of Egyptian history from the end of the New Kingdom to the start of the Late Period, comprising the 21st through 25th dynasties and characterized by political fragmentation and periods of Libyan and Nubian rule over Egypt.

(historical) The period of Egyptian history from the end of the Old Kingdom to the start of the Middle Kingdom (comprising the Seventh/Eighth, Ninth, Tenth, and early Eleventh dynasties), characterized by a loss of central authority in favor of local nomarchs.

(historical) The period of Egyptian history from the end of the Middle Kingdom midway through the 13th dynasty to the start of the New Kingdom at the beginning of the 18th dynasty, characterized by political disintegration and later the conquest of Egypt by the Hyksos.

(astronomy) The sidereal year of a planet. (I.e., in the definition for "sidereal year", replace "Earth" by the given planet.)

(astronomy) The sidereal day of a planet. (I.e., in the definition for "sidereal day", replace "Earth" by the given planet.)

(politics) The last few days before a parliament is dissolved in which important legislation must be concluded