Immensity (noun)

1. The state or quality of being immense; vastness.
2. A vast space or expanse.
3. The immense nature of something.

Origin:

From old french 'immensité', from latin 'immensitas', from 'immensus', meaning 'unmeasured, boundless'.

Examples:

1. The immensity of the universe is difficult for our minds to comprehend.
2. The immensity of the ocean is awe-inspiring.
3. He stood on top of the mountain and gazed out at the immensity of the valley below.
4. The immensity of the problem was overwhelming.
5. She was struck by the immensity of the task ahead of her.