To be the foundation or basis of something, typically hidden or not immediately apparent, providing support or forming the essential groundwork for a particular idea or situation.

Serving as the foundation or basis for something, providing support or forming the underlying structure.

Basic or fundamental; pertaining to the essential or foundational elements of something.

Located beneath or below something else; fundamental or basic, serving as a foundation or support for something else.

Existing beneath the surface or hidden from immediate view; fundamental or essential to the nature of something.