When it comes to medical terminology, the phrase "volume expander" refers to a substance that's used to increase the volume of the blood while maintaining a stable pH balance. While this term is commonly used in the medical field, there are a number of different synonyms that can be used to describe volume expanders. Some of the most common synonyms include fluid replacement therapy, fluid resuscitation, colloids, crystalloids, plasma expanders, blood volume expanders, and hydrating fluids. Each of these terms is used to describe various types of substances and therapies that can be used to increase the volume of blood in individuals experiencing dehydration, blood loss, or other medical conditions.