Existence side by side refers to the coexistence of two or more things or beings. There are numerous synonyms for this phrase, including living together, cohabitating, occupying the same space, sharing the same environment, and coexisting peacefully. Other related terms include collaborating, cooperating, working together, and interacting. When two or more entities exist side by side, it usually implies a harmonious relationship, although it can also refer to conflict or competition. Regardless of the context, having a variety of synonyms for the phrase "exist side by side" can help to avoid repetitive language and add depth and nuance to your writing.