The Collaborative International Dictionary
Triniunity
Triniunity \Trin`i*u"ni*ty\, n. [See Trinity, and Unity.] Triunity; trinity. [Obs.]
As for terms of trinity, triniunity, . . . and the
like, they reject them as scholastic notions.
--Milton.
Wiktionary
triniunity
n. (obsolete form of triunity English)