Webster's Revised Unabridged Dictionary · 1913

Billow

Billow ({not transcribed}) , noun

[Compare Icelandic bylgja billow, Danish bolge, Swedish bolja; akin to Middle High German bulge billow, bag, and to English bulge. See Bulge.]

1.
A great wave or surge of the sea or other water, caused usually by violent wind.
Whom the winds waft where'er the billows roll. — Cowper
2.
A great wave or flood of anything. — Milton

Billow ({not transcribed}) , intransitive verb

To surge; to rise and roll in waves or surges; to undulate.
The billowing snow. — Prior