In`ter*reg"num (?), n.; pl. Interregnums (#). [L., fr. inter between + regnum dominion, reign. See Reign, and cf. Interreign.]
The time during which a throne is vacant between the death or abdication of a sovereign and the accession of his successor.
Any period during which, for any cause, the executive branch of a government is suspended or interrupted.
© Webster 1913.