The term that describes how easily a fluid can pass through solid material is permeability.

Here's a breakdown:

* Permeability: A measure of a material's ability to allow fluids to flow through it.

* High permeability: Means the fluid flows easily through the material (like water through sand).

* Low permeability: Means the fluid has difficulty flowing through the material (like water through clay).

Permeability is an important concept in many fields, including:

* Geology: Understanding groundwater flow and oil/gas exploration.

* Civil Engineering: Designing filters, dams, and other structures.

* Environmental Science: Studying the movement of pollutants in soil and water.