He glances around him in a circular direction to indicate the vastitude of the question, a vastitude which is to be inferred from the established fact of the ambient desert.
-- Raymond Queneau, translated by Barbara Wright, The Blue Flowers, 1965
The setting was an outcropping of stones amid a dun, dust-scoured vastitude, somewhere in the interior of China.
-- Neal Stephenson, The Diamond Age, 1995
Vastitude is derived from the Latin word vastitūdō, a combination of vast, meaning "of great size" and the suffix -tude, which appears in abstract nouns like latitude. The connective vowel -i- is commonly used in compounds of Latin or Greek words.