reign vs overarch

reign is a noun but overarch is not a noun.

Word	Noun	Adjective	Verb	Adverb
reign	Yes	No	Yes	No
overarch	No	No	Yes	No

As verbs, overarch is a hyponym of reign; that is, overarch is a word with a more specific, narrower meaning than reign:

Other hyponyms of reign include override, outbalance, outweigh, overbalance, preponderate.

reign (noun)	overarch (noun)
royal authority; the dominion of a monarch
the period during which a monarch is sovereign
a period during which something or somebody is dominant or powerful

reign (verb)	overarch (verb)
have sovereign power	form an arch over
be larger in number, quantity, power, status or importance	be central or dominant