A human chain can be interchangeable with various synonyms to convey the same meaning. It's a term that refers to people standing together in a line, holding hands and creating a chain-like structure. Some synonyms for human chain could be crowd formation, massive gathering, organized group, solidarity chain, or cooperative lineup. Other options may include group link, people connection, or even united support line. The phrasal expressions could vary from person-to-person as well, such as people's chain or heavy crowd link. Nonetheless, these synonyms serve to describe the symbolic or physical union of individuals in a collective manner.