The story
- Latin · borrowed fromcoadūnātus
- English todaycoadunate
The verb is first attested in 1607, the adjective in 1839; borrowed from Latin coadūnātus, perfect passive participle of coadūnō (“to unite, collect or join into one”), see -ate (adjective-forming suffix) and -ate (verb-forming suffix).
Etymology from Wiktionary, CC BY-SA 4.0.