ˈ ̷ ̷ˌ ̷ ̷ noun
1. : a mass or growth of marine plants (as algae)
2. : a plant growing in the sea ; especially : a marine alga (as a kelp, dulse, rockweed, sea lettuce) widely distributed in the ocean, occurring from tide level to considerable depths, floating free or being anchored by specialized holdfasts of the thallus, and including many that are of economic importance (as for food, fertilizer, agar, fiber, potash, or iodine)