The character of being ornamental; capacity of ornamenting; also, an ornament.(noun)
The Century Dictionary (Public Domain)
Use "ornamentality" in a sentence
"Her picture is come home from the frame-maker, and looks very fine indeed in its gilt ornamentality."
"As a practical matter, it’s not a big overlap, because any time there’s an intermixture of functionality and aesthetic elements, that’s not going to qualify for copyright under the useful article doctrine, so there’s not much room for both ornamentality and separability."