Crystalloids are solutions that contain small particles that are soluble in water. There are several synonyms for the word crystalloids, including isotonic solutions, solutes, clear fluids, and homogenous fluids. These solutions have numerous applications, including in medicine, where they are used as intravenous fluids to replace lost bodily fluids. Crystalloid solutions are also widely used in laboratory testing, where they are frequently used to dilute samples for further analysis. Other synonyms for crystalloids include crystalloid fluids, electrolyte solutions, and non-colloidal solutions. Ultimately, the wide range of synonyms for crystalloids reflects the critical role that these solutions play in diverse fields and settings.