Expanse (noun)

1. A wide and open space or area.
2. A large area of land or water.
3. A wide and extensive area of something.

Origin:

Late middle english: from old french, or from latin expansus "spread out", past participle of expandere, from ex- "out" + pandere "spread".

Examples:

1. An expanse of grass stretched out in front of the house.
2. The ocean was an endless expanse of blue.
3. The expanse of the desert was overwhelming.
4. The expanse of the night sky was breathtaking.
5. The expanse of the city stretched out before them.