The process by which water moves between the intracellular and extracellular compartments is called osmosis.

Here's a breakdown:

* Osmosis is the movement of water molecules across a semi-permeable membrane from a region of high water concentration (low solute concentration) to a region of low water concentration (high solute concentration).

* The intracellular compartment refers to the space within cells.

* The extracellular compartment refers to the space outside cells, including blood plasma, interstitial fluid, and lymph.

This movement of water is crucial for maintaining the proper balance of fluids and solutes within the body. It helps cells function properly, transports nutrients, and removes waste products.