The quality of having great spatial extent, esp. horizontally; vastness, spaciousness.

Of a material thing: great size, volume, or bulk; massiveness.

Largeness, extent, greatness (literal and figurative). Also: an instance of this.

Largeness of scope, extent, or reach; the quality of encompassing, including, or affecting a great number of people or things; comprehensiveness.

The state or quality of being spacious, wide, or commodious; extensiveness of area or dimensions; roominess. Also figurative and in extended use.

The quality of being vast; immensity.

The quality of being vast or immense; vastness, vastitude.

Vastness, vastitude.

Spaciousness; extensiveness; (in later use) spatiality. Now rare.

The quality of being vast; immensity.

Transverse dimension; extent as measured from side to side; breadth, width of a surface, as opposed to length; also occasionally spaciousness. Now…

That which is immense. An (or the) immense extent of something; a thing of immense or unmeasured extent.