interregnum vs lag

interregnum and lag both are nouns.

Word	Noun	Adjective	Verb	Adverb
interregnum	Yes	No	No	No
lag	Yes	No	Yes	No

As nouns, lag is a hypernym of interregnum; that is, lag is a word with a broader meaning than interregnum:

Other hypernyms of interregnum include interim, meantime, meanwhile.

interregnum (noun)	lag (noun)
the time between two reigns, governments, etc.	the act of slowing down or falling behind
	one of several thin slats of wood forming the sides of a barrel or bucket
	the time between one event, process, or period and another

interregnum (verb)	lag (verb)
	throw or pitch at a mark, as with coins
	cover with lagging to prevent heat loss
	hang (back) or fall (behind) in movement, progress, development, etc.
	lock up or confine, in or as in a jail