v. i. To swell or heave like a wave of the sea. [ R. ] Lisle. [ 1913 Webster ]

n. [ Cf. Icel. bylgja billow, Dan. bölge, Sw. bölja; akin to MHG. bulge billow, bag, and to E. bulge. See Bulge. ] 1. A great wave or surge of the sea or other water, caused usually by violent wind. [ 1913 Webster ]

Whom the winds waft where'er the billows roll. Cowper. [ 1913 Webster ]

2. A great wave or flood of anything. Milton. [ 1913 Webster ]

v. i. [ imp. & p. p. Billowed p. pr. & vb. n. Billowing. ] To surge; to rise and roll in waves or surges; to undulate. “The billowing snow.” Prior. [ 1913 Webster ]

adj. [ p. pr. & vb. n. of billow, verb ] 1. rising in billows. billowing smoke [ WordNet 1.5 ]

2. stormy; affected by storms; -- of weather, used prenominally. calm
Syn. -- billowy, surging. [ WordNet 1.5 ]

a. Of or pertaining to billows; swelling or swollen into large waves; full of billows or surges; resembling billows. [ 1913 Webster ]

And whitening down the many-tinctured stream,
Descends the billowy foam. Thomson. [ 1913 Webster ]