seaweed

noun
  1. A general term for various types of marine algae, especially those that are large and multicellular, found in the ocean or on rocky shores. noun
    The beach was covered with seaweed after the storm.
    Seaweed is often used in Asian cuisine, particularly in sushi rolls.
  2. Any of numerous marine plants and algae, such as kelp, that grow in the ocean and are used as food, fertilizer, or in various industrial applications. noun
    Farmers use seaweed as a natural fertilizer for their crops.
    Certain types of seaweed are harvested for their gelatinous substances, which are used in food processing.