Causal nexus is a term used to describe the relationship between two events, where one event is responsible for the other. If you want to expand your vocabulary, there are a number of synonyms that can be used instead of causal nexus. One common synonym is causal relationship, which refers to a direct link between two events. Another synonym is cause-effect relationship, which implies that one event causes another in a predictable way. Other synonyms for causal nexus include causal connection, causal association, and causal link. No matter which synonym you choose, the term refers to a fundamental concept in cause and effect relationships that is useful in a variety of fields, from science to philosophy.