The water that fills up spaces between rock and soil is called groundwater.

Here's a little more detail:

* Ground water is the water found beneath the Earth's surface, in the spaces between rocks and soil.

* This water is not always visible, but it plays a vital role in our environment. It can be accessed through wells and springs.

* The spaces between rocks and soil are called pores. The size and interconnectedness of these pores determine how much water can be held and how easily it can move.

Let me know if you have any more questions about groundwater!