expanse
n. countable B2 Upper Intermediate US //ɪkˈspæns// UK //ɛkspˈæns// ex·panse
n. a wide, open area of land, water, or sky. It describes a space that feels very large and goes on for a long distance.
n. a wide, continuous area or stretch of something, typically land or sea. Often used to emphasize the vastness or uninterrupted nature of a physical space.
The blue expanse of the ocean stretched out before us.
From the top of the hill, we could see the vast expanse of the valley below us.
The hikers were struck by the silent expanse of the desert, where the horizon seemed to recede further with every step they took toward the distant mountains.
From Latin expansum, from expandō.
Usage
Often paired with the preposition 'of' to describe the material or element filling the space.