An interregnum (plural interregna or interregnums) is a period of discontinuity or “gap” in a government, organization, or social order. Archetypally, it was the period of time between the reign of one monarch and the next (coming from Latin inter-, “between” and rēgnum, “reign” [from rex, rēgis, “king”]), and the concepts of interregnum and regency therefore overlap. Historically, the longer and heavier interregna were typically accompanied by widespread unrest, civil and succession wars between warlords, and power vacuums filled by foreign invasions or the emergence of a new power. A failed state is usually in interregnum.