|Noah Webster's Dictionary|
1. (n.) Popularly, any plant or plants growing in the sea.
2. (n.) Any marine plant of the class Algae, as kelp, dulse, Fucus, Ulva, etc.
Seaweed (1 Occurrence)
Jonah 2:5 The waters were circling round me, even to the neck; the deep was about me; the sea-grass was twisted round my head. (See NIV)