The phrase "joining of forces" refers to the act of combining or uniting different groups or individuals towards a common goal or objective. There are several synonyms for this phrase, including alliance, coalition, merger, partnership, collaboration, amalgamation, fusion, assemblage, union, and integration. All of these words suggest the coming together of two or more entities to work together and achieve a shared aim. Whether it's in politics, business, or social affairs, the joining of forces is often necessary to achieve success and make a significant impact. So the next time you want to describe the coming together of different parties, consider using one of these synonyms to add variety to your writing.