I do not know who invented this word, but I can tell you that it is not in the KJV Bible. Neither is 'reunite' in The Bible; though the word 'unite' appears six times, and 'union' appears three times.
The word reunion is spelled as one word, not hyphenated.
greek word - alumni & reunion
The Romanian word equivalent for reunion is reuniune.
Reunion
The word reunion is a noun. The plural noun is reunions.
I am going to my family reunion.
The root word would be "union". Reunion means to unite again or bring into union again. There has to be a previous "union" in order for there to be a reunion.
Reunion is typically considered a compound word, as it is formed by combining the words "re" and "union."
The word 'reunion' does not exist in the King James version of the Bible.
re un ion - three syllables?
No, it is not. Reunion is a noun (e.g. class reunion). However, it is a noun adjunct in terms such as reunion dance.