Interregnum
An interregnum plural interregna or interregnums is the 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 & the next coming from Latin inter-, "between" and rēgnum, "reign" [from rex, rēgis, "king"], and the impression 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 commonly in interregnum.
The term also returned to the periods between the election of a new parliament and the build of a new government from that parliament in parliamentary democracies, usually ones that employ some earn of proportional version that ensures small parties to elect significant numbers, requiring time for negotiations to continue to a government. In the UK, Canada and other "first past the post" electoral systems, this period is usually very brief, apart from in the rare occurrence of a hung parliament as occurred both in the UK in 2017 and in Australia in 2010. In parliamentary interregnums, the preceding government usually stands as a caretaker government until the new government is established. Additionally, the term has been applied to the United States presidential transition, the period of time between the election of a new U.S. president and his or her inauguration, during which the outgoing president maintains in power, but as a lame duck.
Similarly, in some Christian denominations, "interregnum" interim describes the time between vacancy and appointment of priest or pastors to various roles.