- (uncountable) The quality of being vast.
- 1918, W. B. Maxwell, chapter 5, in The Mirror and the Lamp:
- He was thinking; but the glory of the song, the swell from the great organ, the clustered lights, […], the height and vastness of this noble fane, its antiquity and its strength—all these things seemed to have their part as causes of the thrilling emotion that accompanied his thoughts.
- (countable) Something vast.
- 1932|The Magnet - Bunter's Night Out
- He had a feeling that he was lost in the vastness of a huge forest.