billowinessn.
Etymology: < billowy adj. + -ness suffix.Previous versions of the OED give the stress as: ˈbillowiness.
the world > space > shape > unevenness > [noun] > undulating form
1826 N. T. Carrington Pref. 12 The singular billowiness of the ground causes..some delicious varieties of light and shade.
This entry has not yet been fully updated (first published 1887; most recently modified version published online June 2019).