What is the term for a geologic formation that can yield water to a well or spring?

An aquifer is a geologic formation capable of storing and transmitting water, which makes it essential for yielding water to wells and springs. This formation typically comprises permeable materials, such as sand, gravel, or limestone, which allow water to flow through it. The water in an aquifer can be replenished through precipitation or surface water infiltration, creating a sustainable source of freshwater.

In contrast, an applicant refers to a person applying for a position or request, which is unrelated to geological formations. Grout is a material used in construction to fill spaces, seal joints, or provide structural support, and does not pertain to the yielding of water. The term department is a division of a larger organization, like a governmental body or a company, and again bears no relevance to the context of water yielding in geology. Therefore, aquifer is the only correct term that directly associates with the concept of a geologic formation yielding water.