to swell out, puff up, etc., as by the action of wind
billowing (ˈbillowing) adjective, noun
Word origin of 'billow'
from Old Norse bylgja; related to Swedish bōlja, Danish bölg, Middle High German bulge
(Spanish) hincharse, ondular
The shining radiance of the sun goes through the fenestrae of this salon slicing the darkness in half, making the air bleed with the carmine of the tall sheer drapes billowing in the late afternoon zephyr.
Brand, Seph THE HAND OF MADNESS (2019)
The curtains billowed in the breeze.