kelp

noun

• a large brown seaweed that typically has a long, tough stalk with a broad frond divided into strips. Some kinds grow to a very large size and form underwater “forests” that support a large population of animals.

  • Family Laminariaceae, class Phaeophyceae, including the genera Laminaria (used in some areas as manure) and Macrocystis (harvested in the US as a source of algin)
• the calcined ashes of seaweed, used as a source of various salts.