Origin of triad
OTHER WORDS FROM triadtri·ad·ic, adjectivetri·ad·ism, noun
How to use triad in a sentence
Truth would be a triadic relation, but of a different sort from that expounded by Mr. Russell.Essays in Experimental Logic|John Dewey
As the total system falls into three parts, so every part of the system follows the triadic law.
For Kempe's triadic relation in question can be stated, in what he calls its obverse form, in perfectly symmetrical terms.