I. ˈbi-(ˌ)lō noun
Etymology: Old Norse bylgja; akin to Old High German balg bag — more at belly
Date: 1552
1. : wave ; especially : a great wave or surge of water
2. : a rolling mass (as of flame or smoke) that resembles a high wave
• bil·lowy ˈbi-lə-wē adjective
II. verb
Date: 1585
intransitive verb
1. : to rise or roll in waves or surges
2. : to bulge or swell out (as through action of the wind)
transitive verb
: to cause to billow