Coextend is a term that refers to an object, phenomenon or an idea that extends along with another entity. It is often used to describe things that are interconnected, like two rivers, two people or two paths. Synonyms for the word coextend include the phrases "go hand in hand", "exist together", "parallel" and "correspond". These words describe the same concept of existing together harmoniously and being able to complement each other. Other synonyms for coextend include "cohabitate", "coexist" and "share common ground". Each of these words represents the idea of two entities existing side-by-side, sharing space and coexisting in a mutually beneficial way.