To billow is to swell outward or to move or rise up as if caused by waves.
(verb)See billow in Webster's New World College Dictionary
noun
Origin: ON bylgja: see belly
intransitive verb
transitive verb
See billow in American Heritage Dictionary 4
noun
Origin:
Origin: From Old Norse bylgja, a wave; see bhelgh- in Indo-European roots
.Related Forms:
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