rondure
A graceful curvature or round object; a ring; a sphere.
countable
That heaven's air in this huge rondure hems.
[…]all things rareThe quality of being round; roundness.
uncountable
Where it comes from
Borrowed from French rondeur (“roundness; round object”), from rond (“round”) + -eur (suffix forming agent nouns from verbs).
Adapted from the Wiktionary entry rondure (CC BY-SA 4.0).