The phrase "shoulder to shoulder" means to stand or work closely alongside someone, usually to show solidarity or support. Some synonyms for this phrase include side-by-side, together, in unison, hand in hand, and arm in arm. These words all convey a feeling of togetherness and shared effort, which is a powerful message in times of struggle and hardship. The phrase "shoulder to shoulder" originated from military tactics when soldiers stood closely together for protection and support. However, it has since evolved into a more figurative expression, used to demonstrate mutual reliance and collaboration in a wide range of contexts.