Billowing means swelling and rolling outward in great soft waves. Smoke, sails, curtains, a long skirt in the wind.
The size is what the word promises, since a billow is a large rolling wave and nothing small billows. It suits smoke above all, and billowing smoke is close to a fixed phrase in news reports. Fabric billows when air gets under it, which is what makes it such a favourite of photographers. The verb is billow and the noun is a billow.
1adjectivebillowingSwelling and rolling outward in large soft waves.
“Billowing smoke could be seen from the next village.”
Proto-Indo-European
*bʰelǵʰ-
Old Norse
bylgja
Middle English
*bilwe
English
billow
English, today
billowing
billow comes from Middle English bilwe, from Old Norse bylgja. From Middle English bilwe, borrowed from Old Norse bylgja, from Proto-Germanic bulgijō. Cognates include Danish bølge (“wave”); Norwegian Bokmål bølge (“wave”), Norwegian Nynorsk bylgje (“wave”); Swedish bölja (“wave”); German Low German Bulge, Bulg, Bülg (“billow, wave”); German Bulge (“billow, wave”). Compare bellow, bawl.
Etymology from Wiktionary, CC BY-SA