Dyadic is a word that refers to something that involves two individuals or parties. When looking for synonyms for the word dyadic, some good options include bilateral, bipartite, dual, duplex, and twofold. Other possible synonyms might include binary, double, duplicitous, or paired. Each of these words carries a slightly different connotation and may be more appropriate in certain contexts. For example, the word bilateral is often used in discussions of international relations, while the word duplex might be more appropriate when discussing a physical structure that is divided into two parts. Overall, there are many different words that could be used as synonyms for the word dyadic, depending on the context in which it is being used.