1. The time between two reigns, governments, or ministries.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• unterregnum,
• jnterregnum,
• knterregnum,
• onterregnum,
• 9nterregnum,
• 8nterregnum,
• ibterregnum,
• imterregnum,
• ijterregnum,
• ihterregnum,
• inrerregnum,
• interregmum,
• interregnim,
• interregnun,
• interregnuum,
• interrugnum,
• interragnum,
• interregnem,
• interregenun,
• intergenum

• interrelated,
• internment,
• interfere,
• interior,
• interest,
• interlace,
• interiorize,
• interred,
• intercede,
• interfering,
• intervene,
• interference,
• interested,
• internee,
• interbred,
• internuncio,
• interlope,
• interestedness,
• interpretive,
• interruption,
• interpreter,
• Internode,
• interrogate,
• interrelate,
• interrupt,
• interpreted,
• interiorise,
• interrupter,
• in theory,
• interpose,
• interrelation,
• interlard,
• interpret,
• interrogator,
• in utero,
• interview,
• interpreting,
• interface,
• interrupted,
• interlude,
• interferon,
• interesting.

The adjective form of the word "interregnum" is "interregnumal".