Interstitial fluid can be described as:

Interstitial fluid is the fluid that exists in the spaces between cells in tissues. It plays a vital role in the transport of nutrients, waste products, and other substances to and from cells. This fluid serves as a medium through which cells can exchange materials with the blood and surrounding areas, helping to maintain homeostasis. By filling the gaps between cells, interstitial fluid allows for essential physiological processes, such as osmotic balance and nutrient distribution.

This understanding of interstitial fluid's role emphasizes its importance in cellular function and overall tissue health, distinguishing it from other types of fluid, such as blood (which is contained within blood vessels), pleural fluid (found in the lungs), or digestive fluids (present in the digestive tract). Each of these fluids has its specific location and function within the body, making interstitial fluid unique in its presence and purpose between cells.