translation for "unity" or "union"

Mae Govannen fellow tolkien fans, i am loooking for any word in sindarin or quenya that can mean "union", "unity", "togetherness", "oneness" any word that can describe those ideas or short phrase. After searching for hours i cant find anything to satisfy me on the web. I would appreciate it if you could help me.

I would offer erthad (S. union/uniting)

Thank you very much for your help this is really what I needed.