The state of being a coregent or ruling jointly; a variant of 'coregency.'
From 'coregnant' (one who rules together) + '-cy' (noun suffix). This appears to be an alternative or archaic form of 'coregency.'
English loves creating multiple words for the same concept—'coregency,' 'coregnancy,' and 'coregence' all mean basically the same thing, which shows how language naturally produces synonyms and variants as it evolves.
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