interregnum
‘period intervening between a ruler and his successor, temporary authority exercised during a vacancy’
Lexical development traced from the Tamil root:
Lat. interregnum ‘an interval between two reigns’ < inter ‘between’ + regnum ‘kingship, dominion, rule, realm’ < regere ‘to rule, to direct, keep straight, guide’ < reg < reg- < Tamil aracaṉ