A large rolling wave. The word is used figuratively of overwhelming trouble and sorrow, as when the psalmist describes God's waves and billows passing over him.
Definition
A billow is a great rolling wave. The word may also describe trouble or sorrow that overwhelms a person like waves passing over him.
Biblical Usage
The psalmist uses waves and billows figuratively for overwhelming trouble; the same imagery appears in Jonah’s prayer.
Historical Bible Dictionaries
International Standard Bible Encyclopedia (ISBE)
<p>bil'-o (gal, "a great rolling wave"): Figuratively, of trouble, "All thy waves and thy billows are gone over me" (Ps 42:7; compare <em>Jon 2:3</em>).</p>